
Rnntr ^ ^ ^ ' 
Copyright }J" 



CHEKRIGHT DEPOSm 



p^y 



THE 



PRACTICAL ANATOMIST. 



THE 



PRACTICAL A^^'ATOMIST: 



THE STUDENT'S GUIDE IN THE DISSECTING-ROOM. 



BY 



J. M. ALLEN, M. D., 

LATE PROFESSOR OF ANATOMY IX THE MEDICAL DEPARTMENT OP PENNSYLVANIA COLLEGE ; 
FELLOW OF THE COLLEGE OP PIIYSICIxVNS ; MEMBER OF THE ACADEMY OP 
NATURAL SCIENCES, ETC. 



/^,.. 



"^,1^ 



^•^6 



TWO HUNDRED AND SIXTY-StX ILLUSTRATIONS. 







P II I L A D E L r II I A : 

B L A N C II A K D AND LEA 

185G. 






^^^:'ix^ 



Entered according to the Act of Congress, in the year 1856, by 

BLANCHARD AND LEA, 

in the Office of the Clerk of the District Court of the United States in and 
for the Eastern District of Pennsylvania. 



PHILADELPHIA : 
T. K. AND P. G. COLLINS, PKINTEKS. 



PREFACE. 



Tn preparing a Treatise on Practical Anatomy for tLe use 
of medical students, I have not been influenced by the hope 
that I should be able to add anything new to the fund of 
knowledge which is to be found in the various vvorks which 
have been vmtten on anatomy; nor have I expected to be 
able to introduce much that would be new to any one who 
has had much experience in teaching practical anatomy. 

As our medical institutions are now organized, the student 
must expect to obtain his knowledge of anatomy from two 
distinct sources — namely, the anatomical theatre, and the dis- 
secting-room. In the anatomical theatre^ he is taught ana- 
tomy after whatever plan is adopted by the Professor of that 
department in the institution with which he happens to be 
connected. Here, every part requiring dissection passes 
through the hands of the Prosector before it is presented to 
him for his inspection, all the parts not at the time under 
consideration having been removed. In this way, the stu- 
dent is taught anatomy, systematically ; he has each sj^stem, 
as the muscular, the vascular, &g., presented to him by itself. 
He is also provided with what is called a tcxt-looh^ in which he 
finds everything presented in the same order as in the lecture- 
room. Thus, in learning anatomy in this way, he is required 
to do but little more than to listen to what is told him, to ob- 
serve the illustrations employed by the lecturer, and to read 
his text-book. 

1-^ 



VI PREFACE. 

That some parts of anatomy can be tanght to better ad- 
vantage in tlie anatomical theatre than elsewhere there can 
be no doubt. But there are other parts that can be learned 
far better in the dissecting -room. Among the parts thus 
learned may be included almost everything, whose relations 
must be understood in order to render a knowledge of them 
available in diagnosis and in operative surgery. 

However desirable it may be to have every student become 
a thorough anatomist^ it must be well known to every teacher 
of anatomy that much of what is taught in the lecture-room 
is never fully learned and retained by very many of those who 
graduate in our best institutions ; nor is it necessary that the 
practitioner of medicine or surgery should be so thoroughly 
conversant with the science of anatomy as he who teaches 
it. Yet no one, I presume, will say that the student should 
not learn as much of anatomy as is essential to enable him 
to do justice to those who may confide in his skill or his 
ability to treat disease. As but few of those who enroll their 
names in our colleges as students can ever desire or hope to 
become teachers of anatomy, it is important that their time 
should be appropriated to the study of what will be indis- 
pensable for them to know in the daily routine of practice. 
Impressed with the conviction that the dissecting-room affords 
the greatest facilities for acquiring that knowledge which 
the student, when he becomes a practitioner of medicine, will 
most need, I have endeavored to supply him with what might 
be regarded as his text-looh in the dissecting-room. 

To be a student in the lecture-room is Cjuite different from 
being a student in the dissecting-room. In the latter, the body 
is placed in his hands without any previous dissection having 
been made, and he is required to dissect each part himself. 
To do this, he must avail himself of the experience of some 
one who is familiar not only with the parts to be dissected, 
but with the manipulations necessary to make the proper 
dissections. In offering him this assistance, I Lave not viewed 



PREFACE. VU 

him as a mere passive agent, but as one capable of using Lis 
own faculties, and of exercising bis own skill and judgment 
as occasion migbt require. It bas been my constant aim to 
instil in the dissecting-room a feeling of self-reliance and 
self -dependence ; to make tbe student feel that when be bad 
exposed a part, as a muscle, for example, be could see and 
learn its relations to surrounding parts just as well witb- 
out as witb being told tbem ; tbat be could see witb bis own 
eyes wbetber a muscle lies on tbe outer or inner side of a 
particular artery, and wbetber it must be divided or not in 
cutting down upon tbe latter for tbe purpose of applying a 
ligature to it, or wbetber it may serve as a guide for finding 
tbe vessel, and, if so, in wbat way. In following out tbis 
plan, I bave, wbenever tbe opportunity offered, suggested 
wbat deserved bis special attention, believing tbat a simple 
suggestion would often be of more value to bim tban a wbole 
page occupied in describing wbat a mere bint would prompt 
bim to ascertain or learn witbout assistance. Wbenever I 
bave been able, in tbe dissecting-room, to make a student 
feel a consciousness of bis own ability to become a good 
practical anatomist^ I bave almost invariably bad tbe grati- 
fication of witnessing bis entire success. For tbe trutb of 
tbis remark, I can appeal to hundreds of gentlemen wbo 
are at tbis time engaged in tbe active duties of professional 
life in different portions of tbe United States. 

In tbe dissecting-room, more tban in almost any otber 
place, tbe student should be encouraged to cultivate a habit 
of self -interrogation: to ask himself tbe use of everything be 
dissects, and in what way a knowledge of it can be made 
available to bim, either in understanding the otber branches 
of medical science or in his future practice. To incite in his 
mind such a spirit of self-inquiry has been my constant en- 
deavor throughout the Avork. 

In the division of a subject, I have followed the plan 
which I have fomid, after a trial of many years, to be the 



Vlll PREFACE. 

most convenient and advantageous to students, whose time 
for studying practical anatomy is limited, and who, not un- 
frequently, are compelled to confine their dissections to one 
or two hodies during the session. The body is supposed to be 
divided into five farts ^ and apportioned to as many persons; 
one of whom has the liead and nech^ two have, each an upper 
extremity separately, and the thorax in common; two have, 
each a lower extremity^ including the abdominal and pelvic 
viscera between them. It is expected that all will partici- 
pate in the examination of the parts contained in the three 
great splanchnic cavities, as they cannot be divided. 

Mere arhilrary rules for exposing the parts in any region 
have been, in general, avoided; the position and the relations 
of each organ or part have indicated the method that has 
been adopted for dissecting it. Every part in a region has 
been noticed as it would naturally be met with when the 
student was desirous of studying everything contained in 
that region. 1 have found, that when the attention of a 
student was directed to the relations of a part as well as to 
the part itself, the recollection of the one usually aided him 
in the recollection of the other; that it was merely necessary 
for him to appropriate more time to the study of the parts 
of that reoion. 

o 

In aniiing to make the book as useful as possible, viewing 
the student as a candidate for the practice of medicine and 
surgery, I have not hesitated to ^discriminate, to some ex- 
tent, between different regions and organs in a practical point 
of view; hence, I have dwelt longer on some parts than on 
others, being governed in this respect partly by what I con- 
ceived to be the relative value and importance of the know- 
ledge of any part or organ to the student, and partly by the 
difficulty which I have observed students in the dissecting- 
room, especially beginners, to have in dissecting and under- 
standing them. Thus, I have devoted a large share of time 
and space to the organs contained in the three great splanch- 



PREFACE. IX 

nic cavities, to the organs of the special senses, and to such 
regions as the perineum, the inguinal, the femoral, the ante- 
rior part of the neck, and the axilla. Although the space 
allowed in the original plan of the book did not admit of my 
dwelling long on the medical and surgical anatomy of many 
parts and regions, I have endeavored to direct the attention 
of the student to whatever had a practical bearing, so that he 
could, by referring to works on medicine and surgery, derive 
full advantage from his dissections. To give merely a meagre 
or superficial account of the medical and surgical anatomy of 
a part, I am satisfied, does the student more harm than good. 

There has necessarily been in some places more or less 
repetition. As the dissector wishes merely to know the posi- 
tion and the relations of a part in the region that he is dis- 
secting, the same part, in some instances, is referred to at 
different times, and in different dissections. 

In regard to illustrations, I need only say that the Pub- 
lishers gave me carte-hlanche to select from the whole number 
of drawings contained in the various works which have been 
pu.blished by them. When the value of these illustrations — 
over two hundred and sixty in number— is considered, I am 
confident that the liberality thus manifested by them will be 
duly appreciated by every one who may avail himself of the 
work. There is no Dissector, as far as my knowledge extends, 
which is so fully illustrated as this ; it is hardly possible to 
over-estimate the value of pictorial illustrations in a work on 
practical anatomy. I may be permitted to say that the Pub- 
lishers have spared no expense to make the work, as far as 
it depended on them, in every way acceptable to the medical 
student. 

The artistical appearance of the work speaks the praise of 
those who have had the execution of it in their charge. 

It affords me sincere pleasure to avail myself of this oppor- 
tunity to express my heartfelt thanks to those Gentlemen who, 
while my Pupils, aided me in various ways in examining dif- 



X PREFACE. 

ferent parts of the body for the purpose of extending my ob- 
servations in the science of anatomy. Among them, I am 
happy to speak especially of the labors of H. M. Reynolds, 
M. D., who labored most assiduously for upwards of two 
years as my assistant, principally in making special dissections. 
To W. H. GoBRECHT, M. D., late Demonstrator of Ana- 
tomy in the Medical Department of Penosylvania College, 
I am under very great obligations for the able and valuable 
assistance he has rendered me in revising and correcting the 
sheets as they have passed through the press. 

Although the work has been prepared more especially for 
the student in the dissecting-room, I feel confident that the 
physician will find it adapted to his wants, whenever he may 
wish to refresh his memory on the position and relations of 
any part or organ. 

J. M. ALLEK 

Philadelphia, October, 1856. 



TABLE OF COTs'TENTS. 



General Remarks 25 

PART I. 

DISSECTION OF THE HEAD AND NECK. 

CHAPTER I. 

OP the head. 

Section I. 
Of the Face . 29—40 

Section II. 
Appendages of the Eye outside of the orbit . . 40 — 41 

Section III. 
Dissection of the Soft parts on the upper part of the Cranium 4t — 52 

Section 1Y. 
Dissection of the Membranes of the Brain . . 52 — 56 



XU TABLE OF CONTEXTS. 

Section Y. 

Dissection of the Brain . . . . . .56 

Origin of the Cerebral Xeires ..... 80 

Arteries of the Brain . . . . . .85 

Dnra mater . . . .90 

Secttox TI. 
Dissection of the Appendages of the Eye within the orbit 91 — 99 

Szcnox Til. 

The Eyeball 99—110 

Secxiox Till. 

The Spheno-maxiQary region . . . . . 110 — 120 

SEimox IX. 

Dissection of the Ear ...... 120 — 134 

Section X. 

Dissection of the ^ose . . . . . 134 — 143 

Section XI. 

Topography of the Mouth. Fauces, and Pharynx . 143 — 150 

iSection XII. 

Dissection of the Palate ]50 — 152 

Section XIIL 

Dissection of the Tonsrue ..... 152 — 155 



TABLE OF CONTEXTS. XV 



Section II. 

Dissection of the Cavity of the Abdomen . . . 360 — 420 

Relations of the Abdominal Viscera . . . 366 — SI 5 

Yessels and Nerves of the Yiscera . . . 3t5 — 386 

Dissection of the Yiscera 386 — 410 

Section III. 
Dissection of the Pelvic Viscera .... 420 — 474 
Relations of the Pelvic Viscera in the Male . 435 — 439 
Dissection of the Vessels and IN'erves in the Pel- 
vic cavity . 439—455 

Dissection of the Perineum .... 455 — 4t4 

Section IV. 

Dissection of the Female Organs of Generation . 474 — 489 



CHAPTER 11. 

OP THE LOWER EXTREMITY. 

Section I. 

Dissection of the Anterior part of the Thigh . . 489 — 510 
Anatomy of Femoral Hernia .... 489 — 500 

Section II. 

The Gluteal Region 511—520 

Dissection of the Hip-joint ..... 520 



" '' Articulations of the VertebraB . 525 

Pelvis . . 535 

Section III. 

Dissection of the Back of the Thigh and of the Ham 539 — 552 



XVI TABLE OF CONTENTS. 



Section TV. 



Dissection of the Posterior and the Inner part of the 

Leg 552— 56T 

Section Y. 

Dissection of the Anterior and Outer parts of the 

Leg, and the Dorsum of the Foot . . . 568—582 

Section YI. 

Dissection of the Sole of the Foot .... 582—595 

Section YII. 

Dissection of the Ligaments of the Knee, Leg, and Foot 595 — 616 



LIST OF ILLUSTRATIONS 



FIG 
1. 

2. 

3. 
4. 
5. 



9. 
10. 

11. 
12. 
13. 



PAGE 
External Carotid Artery and its Branches . . . .30 

Veins of the Head and Neck . . . . . .31 

Salivary Glands, in situ ....... 33 

Front View of the Left Eye . . . . . .40 

Tensor Tarsi Muscle ....... 42 

Meibomian Glands . . . . . . .43 

Lachrymal Apparatus and Nasal Duct . . . . .46 

Sinuses of the Dura Mater . " . . . . .64 

Vertical Section of Cranium, showing the Falx Cerebri, Tentorium, etc. 66 
Vertical Section in the median plane, of the Cerebrum, Cerebellum, 

Pons, and Medulla Oblongata . 
Section of Cerebrum, displaying the Lateral Ventricles 
Section of the Cerebral Hemisphere 
Section of the Cerebrum displaying the Surfaces of the Corpora Striata 

and Optic Thalami, the Cavity of the Third Ventricle, and the Upper 

Surface of the Cerebellum ..... 

Superior Surface of the Cerebellum .... 

Inferior Surface of the Cerebellum and a portion of the Medulla Ob 

longata ........ 

Arbor Vitce and the Fundamental Portion of the Cerebellum 

Base of the Cerebrum and Cerebellum, with Cranial Nerves 

Arteries at the Base of the Brain 

Sinuses at the Base of the Brain . 

The Nerves in the Orbit above the Muscles 

The Deep Nerves of the Orbit 

Third, Fourth, and Sixth Pairs of Nerves 

Muscles of the Eyeball 

Transverse Section of the Cavernous Sinus of the Right Side 

Longitudinal Section of the Globe of the Eye 

Ciliary Nerves .... 

Anterior Segment of a Transverse Section of the Globe of the Eye 
Posterior Segment of a Transverse Section of the Globe of the 'Eye 

2-x- 



58 
60 
62 



65 
70 

71 

72 

76 

86 

89 

92 

93 

95 

97 

99 

101 

104 

107 

lOS 



XVlll 



LIST OF ILLUSTEATIONS. 



FIG 

29. 
30. 
31. 

32. 
?? 
34. 
35. 
36. 
37. 
38. 
39. 
40. 
41. 
42. 
43. 
44. 
45. 
46. 
47. 
48. 
49. 
60. 
51. 
52. 
53. 
54. 
55. 
56. 
57. 
58. 
59. 
60. 
61. 
62. 
63. 
64. 
65. 
66. 
67. 
08. 
69. 
70. 
71. 
'79.. 



Side View of the adult Crystalline Lens . 
Triple Division of the Lens and the Course of its Fibre; 
Lens hardened in spirit and partially divided along the three Interior 
Planes ...... 

The two Pterygoid Muscles 

Internal Maxillary Artery 

External View of the Articulation of the Lower Jaw 

Internal View of the Articulation of the Lower Jaw 

Section of Temporo-maxillary Articulation 

Distribution of the Trifacial, or Fifth Pair 

Left Ear in its natural state 

Cartilage of the External Ear with some of its Muscles 

Membrana Tympani .... 

Diagram of the Ear .... 

Ossicles of the Left Ear .... 

External Face of the Bony Labyrinth of the Left Side 

Labyrinth in an inverted position 

Tympanic Nerve ..... 

Cartilages of the ISTose, seen from below . 

Bones and Cartilages of the outer Nose . 

Front View of the Cartilages of the Nose 

Osseous and Cartilaginous Septum of the Nose . 

Outer Wall of the Left Nasal Fossa 

Vertical Section of the Middle Part of the Nasal Fossae 

First Pair or Olfactory Nerves 

The Tongue, in situ .... 

The Tongue, with its Papillae 

Median Section of the Nose, Mouth, Pharynx, and Larynx 
Muscles of the Soft Palate, seen from below and in front 
Posterior View of the Muscles of the Soft Palate 
Dorsum of the Tongue ..... 

Muscles of the Tongue, seen from its lower surface 

Under Surface of the Tongue and Muscles connected with it 

Side View of the Superficial Layer of Muscles on the Face and Neck 

Side View of the Superficial Arteries and Veins of the Face and Neck 

Facial Nerve and Branches of the Cervical Plexus 

Deep-seated Layer of Muscles on the Face and Neck 

Arteries of the Neck and Shoulder .... 

The Heart, with the Great Vessels of the Neck, in sitfi . 
Hypoglossal or Ninth Pair of Nerves and Deep-seated Nerves of Neck 
Vertebral Artery, Carotid and Arch of the Aorta 
Superficial and Deep Muscles of the Anterior Aspect of the Neck 
Nerves of the Tongue, etc. ..... 

Prsevertebral Group of Muscles of the Neck 

Anterior View of the Os Hyoides 

Front View of the Cricoid Cartilage .... 



PAGE 

109 
109 



LIST OF ILLUSTRATIONS. XIX 



FIG. PAGE 



74. Lateral View of the Thyroid Cartilage . 

75. Anterior View of the Left Arytenoid Cartilage 

76. Posterior View of the Left Arytenoid Cartilage 

77. Lateral View of the Epiglottis . 



195 
196 
196 
196 



78. Posterior View of the Articulations of the Cartilages of the Larynx . 198 

79. Front View of the Ligaments of the Larynx .... 198 

80. Lateral View of the Ligaments of the Larynx .... 199 

81. The Larynx from above . . . . . . . 199 

82. Front View of the Crico-Thyroid Muscles . . . .200 

83. Posterior View of the Arytenoid and Crico-Arytenoid Muscles . 200 

84. Vertical Section of the Larynx to show some of its Muscles . . 201 

85. Vertical Section of the Larynx, to show its Internal Surface . . 202 
80. Posterior View of the Muscles of the external portion of the Pharynx . 204 

87. Side View of the Muscles of the Pharynx . . . .205 

88. Side View of the Mammary Gland . . . . .208 

89. Vertical Section of the Mammary Gland .... 209 

90. Superficial Muscles of the Upper Front of the Trunk . . .211 

91. Deeper-seated Muscles on the Upper Front of the Trunk . . 214 

92. Axillary and Brachial Arteries and their Branches . . .216 

93. Brachial Plexus of Nerves and Branches to the Arm . . . 217 

94. Superficial Veins on the Front of the Upper Extremity . . . 219 

95. Lateral View of the Deep-seated Muscles of the Trunk . . 220 

96. Anterior View of the Muscles of the Shoulder . . . .222 

97. First and Second and Part of the Third Layers of Muscles of the Back 226 

98. Fourth and Fifth, and Part of the Sixth Layers of the Muscles of the 

Back ......... 231 

99. The Deltoid Muscle . . . . ' . . .239 

100. Posterior View of the Muscles of the Shoulder with the Deltoid . 240 

101. Posterior View of the Muscles of the Shoulder which strengthen the 

Articulation , . . ... . . . 241 

102. The Ligam-ents of the Scapula and Shoulder-Joint . . . 243 

103. Plan of the Cutaneous Nerves on the Front of the Arm . . 247 

104. Plan of the Cutaneous Nerves of the Back of the Arm and Forearm . 247 

105. Superficial Veins at the Bend of the Arm .... 248 

106. Fascia Brachialis . . . . . . .249 

107. Muscles on the Front of the Arm . . . . .250 

108. Plan of the Nerves of the Arm . . . . . .251 

109. Anterior View of the Deep-seated Muscles of the Arm . . . 255 

110. Lateral View of the Deep-seated Muscles on the back of the Arm . 2iA) 

111. Superficial Layer of the Muscles of the Forearm . . . 200 

112. The Arteries of the Forearm ...... 202 

113. Nerves on the Front of the Forearm ..... 265 

114. Deep Layer of Muscles of the Forearm ..... 266 

115. The Pronators of the Forearm ...... 267 

116. Superficial Layer of Muscles of the Posterior Aspect of the Foroarm . 269 

117. Deep Layer of Muscles on the Posterior Aspect of the Foroarm . 270 



XX 



LIST OF ILLtrSTRATIOXS, 



FIG. PAGE 

118. Nerves on the Back of the Forearm and Hand .... 271 

119. Muscles of the Hand . . . . . . .277 

120. Palmar Interosseous Muscles . . . . . . 280 

121. Dorsal Interosseous Muscles ...... 280 

122. Internal View of the Elbow-Joint . . . . .282 

123. External View of the Elbow-Joint . . . . .282 

124. Ligaments of the Anterior Aspect of the Wrist and Hand . . 284 

125. Diagram of the Five Synovial Membranes of the Wrist- Joint . . 285 
128. Anterior View of the Spinal Marrow . . . . .288 

127. Portion of the Spinal Marrow, with origins of Spinal Nerves . . 289 

128. Transverse Sections of the Spinal Cord ..... 290 

129. Diagram of the Thoracic Mediastina ..... 297 

130. xinterior View of the Heart and its Vessels .... 301 

131. Posterior View of the Heart " " '' , . . . 301 

132. The Pjght Auricle and Ventricle of the Heart laid open . . 303 

133. The Left Auricle and Ventricle of the Heart laid open . . 307 

134. Parts of the Left Ventricle and Aorta laid open, showing the Sigmoid 

Valves ......... 309 

135. Auriculo-Ventricular and Arterial Valves . . . . 311 

136. Posterior View of the External Muscular Layer of the Heart . . 313 

137. The Large Vessels which proceed from the Root of the Heart, with 

their Relations ........ 319 

138. The Larynx, Trachea, and Bronchi . . . . .323 

139. Anatomy of the Heart and Lungs . . . . . 327 

140. Portion of the CEsophagus of an Adult . . . . .328 

141. Course and Termination of the Thoracic Duct .... 331 

142. The Great Sympathetic Nerve . . . . . .332 

143. Ligaments of the Sterno-Clavicular and Costo-Sternal Articulations . 335 

144. Anterior Ligaments of the Vertebr83 and Ligaments of the Ribs . 336 

145. Posterior Ligaments of the Thoracic Portion of the Vertebral Column 

and of the Ribs ........ 336 

146. Superficial and Deep Muscles of the Anterior aspect of the Trunk . 343 

147. Lateral View of the Muscles of the Trunk of the Body . . 347 

148. External Parts concerned in Inguinal and Femoral Hernia . . 351 

149. Deep-seated Parts concerned in Inguinal and Femoral Hernia . . 353 

150. Abdominal Muscles and the Abdominal or Inguinal Canal . . 354 

151. Arteries in the Groin of the Left Side ..... 359 

152. Regions of the Abdomen ...... 361 

153. Viscera of the Chest and Abdomen, in sitA .... 367 

154. Viscera of the Chest and Abdomen ..... 369 

155. Viscera of the Upper Part of the Abdomen, with the Coeliac Artery . 377 

156. Superior Mesenteric Artery and its Branches .... 380 

157. The Portal System . . . . . . .382 

158. Inferior Mesenteric Artery and its Branches .... 384 

159. Abdominal Aorta with its Branches ..... 386 

160. Outline of Stomach . . . . . . .387 



LIST OF ILLUSTRATIONS. XXI 

4 

FIG. PAGE 

161. Front View of the Stomach, with Peritoneal Coat turned off . . 389 

162. Vertical and Longitudinal Section of the Stomach and Duodenum . 390 

163. Cells of the Mucous Membrane of the Human Stomach . . 391 

164. Muscular Coat of the Ileum . . . . . .392 

165. A solitary Gland of the Small Intestine ...'.. 394 

166. Patch of Peyer's Glands . . . . . . . 395 

167. Position and Curvatures of the Large Intestine .... 396 

168. The Caseum, dried and laid open ..... 397 

169. Concave Surface of the Liver, showing its Lobes . . . 399 

170. Portal Canal and Portal Vein, with Hepatic Artery and Duct . . 400 

171. Longitudinal Sectionof an Hepatic Vein . . . 401 

172. The Three Coats of the Gall-Bladder . . . . .403 

173. The Duodenum, Pancreas, and Spleen ..... 404 

174. PJght Kidney and its Supra-Renal Capsule .... 407 

175. A Section of the Kidney, surmounted by the Supra-Renal Capsule . 408 

176. Plan of the Renal Circulation . . . . . - 409 

177. Urinary Organs, in sitA . . . . . . . 411 

178. Lumbar and Sacral Plexuses ...... 414 

179. i\bdominal side of the Diaphragm ..... 418 

180. Bladder and Urethra of a Man, laid open .... 423 

181. Longitudinal^Section of the Bladder, Prostate Gland, and Penis . 425 

182. The Glans Penis .427 

183. A Section of the Corpora Cavernosa and Corpus Spongiosum . . 428 

184. Transverse Section of the Testicle ..... 432 

185. Minute Structure of the Testis ...... 433 

186. Posterior Aspect of the Male Bladder, showing its Muscular Coat . 434 

187. Side View of the Viscera of the Male Pelvis, in situ . . .436 

188. Antero-posterior Section of the Pelvis of a Male . . . 438 

189. Diagram of the Iliac Ai'teries and their Branches . . . 440 

190. Arteries of the Pelvis and Thigh . . . . .442 

191. Lumbar Plexus and its Branches . ■ . . . . 448 

192. A diagram of the Formation and Branches of the Sacral Plexus . 450 

193. Muscles of the Perineum of the Male ..... 458 

194. Superficial and Deep Arteries of the Perineum .... 459 

195. The Perineum, after the removal of the Skin and a portion of the 

Superficial Perineal Fascia ...... 461 

196. Structures contained between the two Layers of the Deep Perineal 

Fascia . . , . . . . . .463 

197. A deep Dissection of the Perineum . , . . . 465 

198. Side View of the Viscera of the Pelvis, showing the distribution of the 

Perineal and Pelvic Fascia; . . . . . .470 

199. Transverse Vertical Section of the Pelvis, showing the distribution of 

the Pelvic Fascia ....... 471 

200. External Organs of Generation in the Virgin .... 476 

201. Uteru?, Ovaries, Fallopian Tub.e^, Round Ligaments, Vagina, and 
Vulva . . . . . . . . \ 479 



XXll LIST OF ILLUSTRATIONS. 

FIG. PAGE 

202. Erectile Structures of the External Organs of Generation in the Female 480 

203. Muscles of the Perineum in the Female ..... 481 

204. Posterior View of the Uterus and its Appendages . . . 484 

205. Vertical Section of the Female Pelvis and Viscera . . . 486 

206. Anterior and Inner Aspect of the Thigh, showing the course and 

branches of the Femoral Artery . . . . .490 

207. Plan of the Cutaneous Nerves on the Front of the Thigh . . 491 

208. Saphenous Opening in the Fascia Lata, Internal Saphenous Vein, etc. 491 

209. Section of the Structures which pass beneath the Femoral Arch . 496 

210. Transversalis Muscle and Fascia ..... 498 

211. Muscles of the Anterior Femoral Region .... 502 

212. Anterior Crural Nerve and Branches . . . . .503 

213. Front View of the Femoral Artery and Primitive and External tliacs 506 

214. Deep-seated Muscles on the inside of the Thigh . . . 508 

215. Muscles of the Gluteal and Posterior Femoral Regions . . . 512 

216. Deep-seated Muscles on the Posterior Part of the Hip-Joint . . 513 

217. Arteries on the Back of the Buttock, Thigh, and Ham . . 515 

218. Branches of the Sacral Plexus to the Hip and Back of the Thigh . 516 

219. Deep Muscles of the Gluteal Region ..... 517 

220. Ligaments of the Pelvis and Hip- Joint ..... 521 

221. Side View of the Ligaments of the Pelvis and Hip-Joint . . 523 

222. Posterior View of the Bodies of three Dorsal Vertebra and their Inter- 

vertebral substance ....... 526 

223. A Lumbar Vertebra and horizontal Section of Intervertebral Substance 527 

224. Vertical Section of two Vertebrge and their Intervertebral Substance . '527 

225. Front View of two Lumbar Vertebra and their Intervertebral Substance 528 

226. Internal View of the Arches of three Vertebrae, showing the Ligamenta 

Sub-flava . . . . . . . .529 

227. Anterior View of the Ligaments connecting the Atlas, the Axis, and 

the Occipital Bone ....... 631 

228. Posterior Ligaments of the Occipito-atloid, and Atlanto-axoid Articu- 

lations ...-..,,. 531 

229. Upper Part of the Vertebral Canal, with the Occipito-axoid Ligament . 532" 

230. Posterior View of the Ligaments connecting the Atlas, the Axis, and 

the Occipital Bone .,,.... 533 

231. The Atlas, and its Transverse Ligament .... 534 

232. Posterior View of the Ligaments of the Pelvis . . . .536 

233. Section of the Pelvis, showing its Ligaments and Sacro-sciatic Foramina 538 

234. Plan of the Cutaneous Nerves on the Posterior Aspect of the Left Leg 540 

235. Internal Popliteal Nerve and some of its Branches on the Right Leg . 541 

236. Superficial Muscles of the Posterior Aspect of the Leg . , . 545 

237. Internal Popliteal and Posterior Tibial Nerves in the Ham and the 

Back of the Leg . . . . . . .546 

238. Arteries in the Popliteal Space of the Right Leg . . , 549 

239. Arteries on the Back of the Right Leg ..... 551 

240. Arteries and Deep-seated Veins on the Back of the Right Leg . . 561 



LIST OF ILLUSTRATIONS. 



XXUl 



FIG. PAGE 

241. Deep Layer of Muscles of the Posterior Tibial Eegion of the Left Leg 565 

242. Plan of the Cutaneous Nerves on the forepart of the Leg, and the Dor- 

sum of the Foot . . . . . . . 569 

243. Superficial Veins of the Front of the Right Leg . . .670 

244. Muscles of the Anterior Tibial Region and Dorsum of the Foot . 673 

245. Anterior Tibial Artery and its Branches . . . . 676 

246. Superficial Arteries on the top of the Foot .... 678 

247. Deep-seated Arteries on the top of the Foot .... 578 

248. The Musculo-Cutaneous and the Anterior Tibial Nerve . . 580 

249. First Layer of Muscles in the Sole of the Foot . . . .587 

250. Arteries on the Back of the Leg and the Sole of the Foot . . 589 

251. Deep-seated Branches of the Arteries on the Sole of the Foot . . 589 

252. Termination of the Posterior Tibial Nerve in the Sole of the Foot , 590 

253. Deep-seated Muscles in the Sole of the Foot .... 592 

254. Third and a Part of the Second Layer of Muscles on the Sole of the 

Foot ......... 592 

255. Dorsal Interossei . . . . . . . . 594 

256. Plantar Interossei ....... 594 

257. Anterior View of the Ligaments of the Knee-joint . . . 598 

258. Posterior View of the Ligaments of the Knee-joint . . . 598 

259. Internal Ligaments of the Right Knee-Joint .... 603 

260. Longitudinal Section of the Left Knee-Joint, showing the Reflections of 

the Synovial Membrane ...... 604 

261. Tibio-fibular, and other Ligaments ..... 606 

262. Posterior View of the Ligaments of the Ankle-Joint . . . 607 

263. Internal View of the Ankle-Joint . . . . .609 

264. External View of the Ankle-Joint . . . . . 609 

265. Vertical Section of the Ankle-Joint and Foot of the Right Side . 611 

266. Ligaments of the Sole of the Left Foot . . . . .612 



THE 



PRACTICAL ANATOMIST 



GENERAL REMARKS. 

Perhaps no part of the course of study wliicli the medical 
student is required to pursue is approached with a stronger 
feeling of reluctance than that of practical anatomy. Nor 
will the neglect of any part of his course cause him more 
regret when actively engaged in the duties of his profession. 
Although it must be admitted that there are some things 
connected with dissecting which are unpleasant, yet, when 
the value of the knowledge which can be acquired only in 
the dissecting-room is considered, these things should not be 
allowed to have the slightest influence on the conduct of the 
student. It is only in the dissecting-room that he can have 
the opportunity of seeing the various organs of the body 
before their relations to each other have been disturbed, or 
of catting and separating the different tissues of which they 
are composed, and by which they are connected together. 
However clearly they may be presented and accurately 
described in the lecture-room, it is impossible that he should 
obtain so correct an idea of them as when he can take them 
in his own hands and examine them for himself. 

There is, perhaps, just reason to apprehend that, for the 
want of having had experience in the dissecting-room, many 
members of our profession are deterred from making post- 
mortem examinations, which would be of great value to 
themselves, as Avell as to medical science. It is hardly to 
be expected that one who had never dissected, or who had 
dissected but very little, would feel himself competent to 
make a satisfactory examination of the internal organs of 
3 



26 GENEEAL REMARKS. 

a dead body. It may be safely averred that the student wlio 
has overcome his feeling of repugnance to dissecting, and 
acquired a fondness for it, will be much more likely, when 
he comes to practice, to avail himself of every opportunity 
which may offer to make a post-mortem examination than 
one who has not had the advantages which the dissecting- 
room affords. 

It is scarcely necessary to say that a thorough practical 
knowledge of anatomy is indispensable to the successful per- 
formance of surgical operations. No student should have a 
desire to graduate with the intention of practising medicine 
without feeling assured that he was qualified to perform, at 
least, a large portion of all the operations which might be 
required within the limits of his own practice. To be obliged 
to send a long distance for some one to operate in a case of 
strangulated hernia, after having exhausted all the means in 
his own poAver to reduce it, might be the indirect cause of 
the death of his patient, sphacelus of the bov^el having taken 
place in consequence of delaying the operation. But it is not 
to be inferred that the knowledge of anatomy to be acquired 
in the dissecting-room is more essential' to the practice of 
surgery than to the practice of medicine. Medical anatomy 
is in every respect as important as surgical anatomy. 

In regard to the time when a student should commence 
his dissections, I have no hesitation in saying that the sooner 
he does it after commencing the study of medicine, the better 
it will be for him. The time which he spends in reading on 
anatomy before he has had an opportunity of seeing the 
parts described is, in a great measure, lost. This, I believe, 
accords with the experience of nine out of every ten who 
have pursued this course. The quickest and easiest way to 
acquire a knowledge of a thing is to see it and handle it, A 
student will acquire a better knowledge of the abdominal 
viscera in examining them two hours in the dissecting-room 
than he could in reading a description of them for a week. 
And it is hardly necessary to say that names are learned mth 
much greater facility when the things which they designate 
can be seen and inspected. This is especially true in anat- 
omy, in which so many things are named from their appear- 
ance, location, function, &c. 

The two great objects to be attained in the study of prac- 
tical anatomy are — first, to learn to dissect ; and second, to 



GENERAL REMARKS. ^ 27 

learn tlie parts dissected. The first is to be accompli shed 
only by care and practice. Dissecting is not merely cutting. 
The parts must be exposed in a dissection clearly and with- 
out mutilation. When the student first begins to dissect, it 
is generally on some muscle. He should proceed with this 
just as slovjly as shall be necessary to remove all the fascia 
which covers it, so as to leave the fibres of the muscle 
clear and distinct. If he commences on the abdomen, he 
should spend at least two hours or more in removing the 
skin and fascia from the external oblique muscle. The 
fascia, which may be raised with the skin in his first dis- 
section, should be made tense by holding it with the forceps, 
or with the fingers, whenever it can be done, and the knife 
carried in the direction of the fibres of the muscles. No 
fascia should be left behind in the progress of the dissection 
to obscure the fibres, or to be removed afterwards in detached 
portions. If he learns to dissect the first muscle right, he 
will have no difficulty afterwards in dissecting muscles in a 
manner satisfactory to himself and to his teacher. He should 
always see that the subject, or part, is placed in a position that 
will render the fibres of the muscle which he is dissecting 
tense. When this cannot be effected by position, hooks may 
be used for the purpose. 

When a part has been dissected, it should never be aban- 
doned until it has been so thoroughly studied and learned that 
the student can give an accurate description of it in his own 
words. It is better that he should not commit to memory 
the language used in the text-books which he reads, except 
such words as have a technical meaning. When the student 
has become familiar with the appearance and relations of 
parts, his attention should be directed to the practical appli- 
cation of this knowledge. If he has, for instance, examined 
the liver in situ^ and its relations to contiguous parts, he 
should then study what would be the effect upon these parts 
when it had increased to two or three times its natural size ; 
or, if an abscess should be formed in it, the different ways in 
which the pus might find an outlet. There is no place where 
he can so well appreciate these things as in the dissecting- 
room, with the subject before him. 

As a subject is usually divided between several gentlemen, 
it is exceedingly desirable that each one should prosecute the 
dissection of the part assigned to him so as not to prevent 



28 GEXERAL REMARKS. 

the otbers from proceeding vrhen they may wish to change 
its position, or remove the part which they are dissecting. 
IsoT should the dissection of a part, when once commenced, 
be delayed longer than is absolutely necessary, as it is liable 
to undergo decomposition, to become mouldy, or so dry and 
hard that it cannot be properly dissected. STo part which is 
not required to be preserved for study, or for protecting other 
parts, should be allowed to remain attached to the subject, or 
to lie on the table after it has been cut off. Nothing contrib- 
utes more to the comfort of a student, when dissecting, than 
to have a cleaii table ; hence he should be particular to see 
that scraps or fluids do not collect on the table or fall on the 
floor around it. It is not necessary, perhaps, even to allude 
to the importance of jjersonal cleanliaess in the dissecting- 
room. Every student should be pro^^ided with a gown, or a 
change of garments, so as to prevent his clothes being soiled. 

To be able to dissect properly and satisfactorily, it is indis- 
pensably necessary to have good instruments. "Whether they 
cost a little more or a little less should have no influence on 
the mind of the student when making a purchase, provided 
they are good. I have repeatedly known "students to become 
disgusted with dissecting for no other reason than their 
attempting it with poor instruments. But, however good 
they may be, they will become dull in using them, and re- 
quire to be sharpened. This should be done as often as 
may be found necessary, as it is impossible to make a good 
dissection with a dull instrument. 

It should be recollected that the dissecting-room is a place 
appropriated to studi/ as well as to dissecting, and that con- 
sequently it is desirable that quietness should be observed by 
those who are engaged in it. The importance of this must 
be apparent to every one who has had any experience in the 
dissecting-room. 



PART I. 

DISSECTION OF THE HEAD AND NECK. 



CHAPTEE I. 

OF THE HEAD. 

Sect. I. — Of the Face. 

The Face is bounded above by the root of the nose, eye- 
brows, and the zygomata ; laterally, by the ears and mastoid 
processes ; below, by the base of the lower jaw, and a line 
drawn from its angle to the apex of the mastoid process on 
each side. As the face is symmetrical, it will be sufficient 
to describe one side. The student, however, may attend 
more especially to the dissection of the muscles on one side, 
and to the vessels and nerves on the other. It is conve- 
nient to consider the face as divided into several regions ; as 
the Parotid, the Masseteric, the Buccal, the Mental, the Labial, 
the Nasal, the Orbital, and the Malar. The locatioi^i of each 
of these divisions is indicated by its name. It is not neces- 
sary for our present purpose to define their boundaries. 

To dissect the face, the head must be placed in a suitable 
position, and changed from time to time, as may be found 
most convenient. The lips and cheeks should be made tense 
by inserting beneath them tow or cotton, and then stitching 
the lips together ; the nose and eyelids should also be made 
tense in the same manner. The integument should be raised 
from below upwards, and from behind forwards. For this 
purpose make an incision, commencing at the symphysis of 
the chin, along the base of the lower jaw to its angle, and 
thence to the apex of the mastoid process, and from this 
point extend it upwards in front of the ear to the zygoma, 
and across above the eyebrow to the root of the nose ; make 
another incision in the median lino from the symphysis of the 

3-K- 



30 



DISSECTION OF THE HEAD AND NECK. 



chin to the termination of the first at the root of the nose. 
These incisions may be commenced and extended, or other 
incisions may be made, as shall be required in the process of 
dissection. As a general rule, no more of the integument 
should be raised than is necessary to expose the parts to be 
examined at the time of the dissection. 

Fig. 1. 




A View op the External Carotid Artery and its Branches. — 1. Left primi- 
tive carotid artery, seen through a section of the sterno-cleido-mastoid muscle. 2. 
Internal carotid artery. 3. External carotid artery. 4. Superior thyroid artery. 
5. A branch to the sterno-cleido mastoideus muscle. 6. Lingual artery. 1. Origin 
of the facial artery. 8. Sub-mental branch. 9. Branch to the sub-maxillary gland. 
10. Facial artery passing over the jaw. 11. Inferior coronary artery. 12. Superior 
coronary. 13. Branch to anastomose with the infra-orbital. 14. Branch to the 
ala nasi. 15. Anastomosis of facial with ophthalmic. 16. Nasal branch of oph- 
thalmic. 17. Its frontal branch. 18. Branch to the orbicularis palpebrarum mus- 
cle. 19. Origin of the occipital artery. 20. Point where it passes under the 
splenius muscle. 21. Posterior auricular artery. 22. Origin of the internal maxil- 
lary. 23. Temporal artery. 24. Transverse facial. 25. Point of division of the 
temporal artery. 26. Anterior temporal artery. 27. Middle temporal artery. 28. 
Posterior temporal artery. 29. Internal mammary artery. 30. Inferior thyroid 
artery. 31. Transversalis cervicis artery. 



THE FACE. 



31 



The Pakotid and Masseteeic regions should be examined 
first, and at the same time. 

Fig. 2. 




A View of the Veins op the Head and Neck. — a. Facial vein. h. Temporal 
vein. c. Transverse facial vein. d. Posterior auricular vein. e. Internal maxil- 
lary vein. /. External jugular vein. g. Posterior external jugular. A, Anterior 
jugular, t. Supra-scapular and posterior scapular. A;. Internal jugular. Z. Occip- 
ital vein. VI. Subclavian vein. 

As the integument is raised and reflected forwards, the 
Platysma Myoides, Fig. 61 (i 4), will be found traversing the 
anterior part of these regions. Its fibres are generally pale, 
and are situated immediately beneath the skin, in which they 
terminate. Some fasciculi are directed towards the angle of 
the mouth; they form the risorius, or laughing muscle, of 
Santorini. 

The Paeotid Fascia is quite thick and dense, forms a 
sheath for the parotid gland, and sends numerous prolonga- 
tions into it. It is continuous below with the cervical, and 
in front with the masseteric fascia. The density of this 
fascia renders inflammation of the parotid gland painful, and 
retards the approach of pus, when formed in the gland, to 
the external surface. 



32 DISSECTION OF THE HEAD AND NECK. 

The Masseteric Fascia is mucli thinner than the parotid. 
Anteriorly, it is lost in the subcutaneous cellular tissue, and 
below, in the cervical fascia. When pus is formed beneath 
this fascia, it has a tendency to pass into the neck. 

There are no vessels of any importance situated between 
the parotid gland and the skin. Some filaments of the 
auricidaris magnus nerve may be traced upwards between the 
skin and the gland. 

The borders of the parotid, as now seen, should be loosen- 
ed up, and their relations carefully observed. 

1. The Upper border is situated just below the zygoma. 
The temporal artery, and branches of the facial and fifth pair 
of nerves, Fig. 62 (s), emerge from beneath this border to 
ascend to the side of the cranium ; the temporal vein, Fig. 2, 
enters the gland at this point. 

2. The Anterior border extends from the zygoma to the 
angle of the lower jaw; it overlaps the masseter, more above 
than below. Comino' from beneath this border will be found 
the following : — 

The Transverse Facial Artery is situated about a 
fourth of an inch below the zygoma. It arises in the sub- 
stance of the gland, from the temporal or external carotid, 
and crossing the upper part of the masseter, is distributed to 
the orbital and buccal regions. 

The Duct of Steno, Fig. 3 (2), will be observed just below 
the artery. It is about the size of a crowquill, and is formed 
by radicals proceeding from the lobules of the gland. It is 
about two inches in length, and in direction corresponds yqtj 
nearly to a line drawn from the meatus of the ear to the centre 
of the upper lip. Its buccal orifice, which is very small, is 
opposite to the upper middle molar tooth, and near the centre 
of the line indicating its direction. It perforates the bucci- 
nator muscle at the anterior border of the masseter. The 
position of this duct should be noticed particularlj-, on account 
of its liability to be injured from accidents, and in surgical 
operations. 

The GrLANDULA SociA Parotidis consists of a few lobules 
situated between the zygoma and the parotid duct, with which 
it communicates by a small duct of its own. It is sometimes 



THE FACE. 33 

The nerves, Fig. 63, consist of the Malar, Buccal, and Max- 



illary branches of the facial. 

■ > Fiff. 3. 




A View of the Salivaey Glands in situ. — 1. The parotid gland in situ, and 
extending from tbe zygoma above to the angle of the jaw below. 2. The duct of 
Steno. 3. The submaxillary gland. 4. Its duct. 5. Sublingual gland. 

The Malar Beanches pass upwards and forwards to 
ramify principally in the orbicularis palpebrarum and corru- 
gator supercilii muscles, and the eyelids. The filaments 
which ascend above the orbit form anastomotic connections 
with the supra-orbital of the fifth pair. 

The Buccal Branches cross the masseter muscle close to 
the duct of Steno. They divide into deep and superficial 
branches. The superficial can be traced beneath the skin to 
the upper lip, the nose, and the lower eyelid. They supply 
filaments to the orbicularis oris, the zygomatici major and 
minor, the levator labii superioris, and the pyramidalis nasi. 
The deep branches send filaments mostly to the remaining 
muscles, and form a plexus, as well as interlace and anasto- 
mose with the infra-orbital of the fifth pair. They also 
anastomose with the internal and external nasal branches of 
the ophthalmic nerve. 

The Maxillary Branches pass over the lower part of 
the masseter, and proceed forwards to the chin. They give 
filaments to the masseter, the buccinator, the depressor 



84 DISSECTION OF THE HEAD AND NECK. 

anguli oris, depressor labii inferioris, levator labii inferioris, 
and the platysma mjoides. They anastomose and interlace 
with the mental branches of the inferior dental nerve, form- 
ing the mental plexus. They also anastomose with the buccal 
branch of the inferior maxillary nerve. The muscles of the 
face are supplied principally by the facial, while the skin and 
mucous membrane derive their supply mainly from the fifth. 

3. The Lower border of the parotid projects somewhat into 
the neck, and rests against the posterior belly of the digas- 
tricus, the stjdo-hyoideus, and that reflection of the cervical 
fascia which is attached to the stylo-maxillary ligament, and 
forms a septum between the parotid and submaxillary regions. 

Near the angle of the jaw the cervical branches of the facial 
nerve escape from the gland, to be distributed in the upper 
part of the neck, while branches of the auricularis magnus, a 
branch of the cervical plexus, enter it. The temporo-max- 
illary vein will also be found here, leaving the gland to form 
the external jugular. The external carotid artery enters it on 
a plane deeper than the digastric and stylo-hyoid muscles, to 
divide into the temporal and internal maxillary branches. The 
internal carotid artery and the internal jugular vein with the 
eighth and ninth pairs of nerves, are situated behind the gland. 

4. The Posterior border rests against the auditory pro- 
cess and concha of the ear above, and the mastoid process 
and stern o-cleido-mastoid muscle below. The posterior au- 
ricular artery and nerve emerge from beneath this border of 
the gland to get behind the ear. 

The gland must now be dissected so as to get a view of the 
vessels and nerves in its substance. 

The main trunk of the facial nerve may be easily found 
by tracing into the substance of the gland one or more of its 
branches which have already been described. It enters the 
gland shortly after leaving the foramen stylo -mastoideum, 
and, after passing upwards and forwards over the external 
carotid, divides into two principal branches, the Temporo- 
maxillary and the Cervico-maxillary. The former subdivides 
into the terrfporal^ malar ^ and buccal; the latter into the max- 
illary and cervical^ Fig. 63. 

The Temporo-Maxillary division is connected by one 
or more branches with the temporo-auricular branch of the 
fifth pair. This last branch passes through the upper part of 



THE FACE. 35 

the gland, and is deeper seated than the facial. The facial gives 
off the following small branches before it enters the gland: — 

The posterior auricular^ which sends filaments to the poste- 
rior and superior mnscles of the ear, and to the posterior belly 
of the occipito-frontalis ; the styloid, which is distributed to 
the stylo-hyoid muscle ; and the digastric, which goes to the 
digastric muscle, and also anastomoses with the glosso-pha- 
ryngeal and pneumogastric nerves. The auricularis magnus 
penetrates the parotid, in which some of its filaments anasto- 
mose with the facial, Avhile others pass through it to the cheek, 
and to the skin behind the ear. 

The external carotid artery enters the gland from below, 
and divides into the internal maxillary and temporal ; it also 
gives off branches to the gland and to the integument and 
masseter in front. The veins in the gland correspond to the 
arteries. 

The gland may now be entirely removed, preserving the 
branches of the facial nerve so that they may be traced to 
their destination, and its relations to the deeper seated parts 
observed. It will be found to fill up several irregularities, 
and to be in relation with the temporo-maxillary articulation, 
the glenoid cavity behind the glaserian fissure, the ramus of 
the inferior maxilla, the styloid and mastoid processes of the 
temporal bone, the internal pterygoid and stylo-glossus mus- 
cles. The internal carotid artery generally occupies a sulcus 
on its internal surface. The removal of this gland is ren- 
dered difficult from its deep-seated projections. It can be 
torn out from the depressions which it occupies, when it 
could not well be dissected out. 

The masseter muscle will be described in connection with 
the spheno-maxillary region ; and the vessels and nerves 
behind the parotid with the deep-seated parts of the neck. 

The Buccal, Mental, Labial, and Nasal Eegions may 
now be dissected and examined together. The principal 
constituents of these regions are the Muscles, Arteries, and 
JSTerves. The Muscles are mostly subcutaneous, and belong 
to the nose and mouth. The principal Artery is the facial, 
with its branches. Besides this, small branches are furnishod 
by the temporal, internal maxillary, and ophthalmic. The 
facial vein is situated on the outside of the facial artery, with 
which it corresponds in its direction and branches. The 
nerves are derived from the fiftli, and facial or portio dura, 



86 DISSECTION OF THE HEAD AND NECK. 

Fig. 63 ( 1 ), of the seventh pair. The branches of the facial have 
been noticed in the description of the Parotid and Masseteric 
regions. Those of the fifth pair are the terminal branches 
of the inferior dental, the buccal, the infra-orbital, and the 
nasal. The inferior dental comes through the mental fora- 
men, which is situated just below the second bicuspid tooth ; 
the buccal enters the buccal region behind the anterior bor- 
der of the masseter ; the infra-orhital emerges from the infra- 
orbital foramen in the upper part of the canine fossa ; the 
nasal comes from the inner can thus of the eye, and from the 
junction of the lower end of the nasal bone with the cartilage. 
To dissect these parts, the skin must be reflected forwards 
to the median line, and upwards as far as the root of the 
nose and the attached border of the lower eyelid. 

The Platysma Myoides is lost in the lower part of the 
face. The posterior fasciculi which cover the facial artery 
and the lower portions of the parotid gland and masseter 
muscle, terminate in the subcutaneous areolar tissue and a 
fasciculus which turns forwards towards the angle of the 
mouth, called by Santorini the risorius novus. The middle 
fasciculi blend with the depressor anguli oris and depressor 
labii inferioris muscles. The anterior fibres mix with those 
of the opposite side. 

The superficial fascia may now be removed in detached 
portions while exposing the muscles, arteries, and nerves. 

The facial artery, Fig. 1 (i o), is subcutaneous throughout its 
whole course, except where it passes beneath the Z3^gomatici 
major and minor muscles, and can be easily traced. Its 
branches, consisting of the masseteric, mental, inferior and 
superior coronary and nasal, are irregular in their origin, 
and must be looked for as the main trunk is dissected from 
below upwards. The position of the facial artery where it 
rests upon the inferior maxilla should be noticed, as pressure 
applied to it at this point Avill arrest hemorrhage from it or 
any of its branches. 

The Orbiculaeis Oris, Fig. 61 (i s), is situated in the lips, 
the principal part of which it forms. It consists of two fas- 
ciculi, one for each lip. These blend at the angles of the 
mouth with the buccinators, and other muscles ioserted at 
these points. To dissect this muscle, the lips must be made 
tense. Its external surface is mixed, more or less, with fat, 



THE FACE. 37 

and adheres closely to the skin. The labial glands are placed 
between its inner surface and the m aeons membrane. Its 
action is to close the month, and antagonize the muscles 
inserted into the lips. 

The Depressor Anguli Oris, or Triangularis, Fig. 61, 
arises from a ridge on the outer surface of the inferior max- 
illa, between the insertion of the masseter and the mental 
foramen. The fibres converge, pass upwards, and are inserted 
into the angle of the mouth. It partly overlaps the depres- 
sor labii inferioris and buccinator muscles, from which it is 
readily distinguished by the different direction of their fibres. 
It depresses the angle of the mouth, as its name indicates. 

The Depressor Labii Inferioris, or Quadratus Menti, 
Fig. 64 (i o), arises from the base of the inferior maxilla, com- 
mencing near the symphysis of the chin, and extending 
outwards a short distance beneath the preceding muscle. 
Its fibres pass upwards and inwards, and are inserted into 
the orbicularis and skin of the lower lip. It is difficult to 
make a clean dissection of this muscle, on account of the 
adipose substance mixed with its fibres. The terminal 
branches of the inferior dental artery and nerve emerge from 
the mental foramen under this muscle. By detaching a 
small portion of the mu.scle from its origin below the second 
bicuspid, and raising it up, the foramen will be found and 
the nerve escaping from it. From this point its branches 
can be easily traced upwards to the skin and mucous mem- 
brane of the lip, and upwards and outwards where they 
interlace with the facial nerve, to form the mental plexus. 
This nerve is sensor, and supplies, besides the lips, the lower 
and inner part of the face generally. 

The Levator Labii Inferioris, or Levator Menti, Fig. 
64 (i i), is situated between the mucous membrane and the last 
muscle. _It arises from the alveolar process opposite the in- 
cisor teeth; its fibres radiate as they pass downwards and 
forwards, and are inserted into the integument of the chin. 
The lower part of it is blended with fat. To expose it, the 
lip should be everted, and the mucous membrane dissected 
away. It elevates the lower lip by drawing up the chin. 

The Buccinator, Fig. 64 (s), is a broad, thin muscle, located 
in the cheek. It has three origins; tlio loiccr one arins Iroiu 
4 



38 DISSECTION OF THE HEAD AND NECK. 

t"be external surface of tlie alveolar process of the inferior 
maxilla in front of the coronoid process; the upiJer one from 
the alveolar process of the superior maxilla, in front of the 
pterygoid process ; and the middle one from the pter jgo-max- 
illary ligament, which stretches from the pterygoid to the base 
of the coronoid process, and to which the superior constrictor 
muscle of the pharynx is also attached. From these different 
origins its fibres converge and pass forwards to the angle of 
the mouth to be inserted^ the inferior ones into the upper, 
and the superior ones into the lower lip. This muscle is 
separated behind from the ramus of the inferior maxilla and 
masseter, by a mass of fat, also by two of the buccal glands 
called molar. It is perforated by the duct of Steno. It is 
crossed transversely by the buccal branches of the facial and 
fifth pair of nerves. The facial artery and vein pass over it 
vertically. The buccal glands separate its internal surface 
from the mucous membrane. It draws the angle of the mouth 
backwards, and makes the lips tense ; assists in expelling the 
contents of the mouth, and antagonizes the tongue in keeping 
the food in the process of mastication between the teeth. 

The Zygomaticus Ma joe, Fig. 61 (i 3), arises from the 
malar bone, just above its lower border, passes downwards 
and inwards, and is inserted into the angle of the mouth. It is 
generally surrounded by more or less fat, and its upper part 
is covered by the orbicularis palpebrarum; it crosses over the 
facial artery and vein. Its action is to draAV the angle of 
the mouth upwards and backwards, as in smiling. 

The Zygomaticus Minok, Fig. 61 (1 2), is often a fasciculus 
from the orbicularis palpebrarum. When a distinct muscle, 
it arises from the malar bone, above the last muscle, and is 
inserted into the upper lip with the levator labii superioris, 
with which it acts, at the same time drawing the lip outwards. 

The Levatok Labii Supeeioris, Fig. 61 (s), arises from the 
anterior border of the floor of the orbit, above the canine 
fossa, where it is overlapped by the orbicularis palpebrarum. 
Its fibres converge as they pass downwards to be inserted 
into the skin of the upper lip, and the orbicularis oris. All 
the lower part of this muscle is subcutaneous. Its action is 
indicated by its name. 

The infra-orhital nerve and artery will be found escaping 
from the infra-orbital foramen, beneath the upper part of this 



THE FACE. 89 

muscle. To expose these, cut down tlirougli tlie muscle in 
the direction of its fibres, upon the foramen, and gently raise 
the nerve, when its filaments will be seen to radiate upwards 
to the lower eyelid, inwards to the nose, downwards to the 
upper lip, and outwards and downwards to the cheek. They 
intermix and anastomose with the facial to form the infra- 
orhital plexus. It requires a good deal of care and patience 
to trace these filaments to their termination. The infra- 
orbital artery is one of the terminal branches of the internal 
maxillary. It inosculates with, the facial, transverse facial, 
and ophthalmic. 

The Levator Anguli oris, or Caninus, Yig. 64 (e), arises 
from the canine fossa, below the infra-orbital foramen, and 
beneath the preceding muscle ; passes downwards, and is 
inserted into the angle of the mouth. It raises the angle of 
the mouth, and antagonizes the depressor anguli oris, with 
which some of its fibres are continuous. 

The Levator Labii Superioris Al^que Nasi, Fig. 61(8), 
arises from the upper part of the nasal process of the superior 
maxilla. It passes downwards on the side of the nose, 
divides into the nasal and labial portions, and is inserted^ the 
former into the ala of the nose, and the latter into the upper 
lip. Its name indicates its use. 

The Compressor Kasi, or Triangularis Kasi, Fig. 64 (s), 
is partly concealed by the preceding muscle. It arises from 
the inner part of the canine fossa, passes forwards to spread 
out over the ala of the nose, and is inserted into a thin 
aponeurosis, common to it and its fellow on the opposite side ; 
it is also connected with the pyramidalis. It compresses the 
nostril when it acts alone, but may expand it when it acts 
in conjunction with the pyramidalis. 

The Depressor Labii Superioris Aljeque Nasi, or 
Myrtiformis, Fig. 64 (7), is exposed by everting the upper 
lip, and dissecting off the mucous membrane on the side of the 
fraenum. It arises from the alveolar process of the superior 
maxilla in front of the incisor teeth, passes upwards and 
forwards, and is inserted into the upper lip and the fibro- 
cartilage of the ala and septum of the nose. Its name indi- 
cates its actions. 

The Pyramidalis Nasi, Fig. 64 (3), appears to bo a fascicu- 
lus of the occipito-frontalis prolonged downwards on the nose. 



40 



DISSECTION OF THE HEAD AND NECK, 



It is inserted into the aponeurosis of tlie compressor nasi. It 
causes the vertical ridge sometimes seen at the root of the 
nose. The integnment of the nose is supplied with nerves 
from the infra-orbital and the internal and external nasal. 
The facial artery, after giving off the branches already 
ennmerated, ascends to the forehead between the eyebrows ; 
its terminal branch is called the angularis. 



Sect. II. — Appendages of the Eye outside of the Oebit. 

The dissection of the orbital region will embrace those 
appendages of the eye which can be exposed and studied 
without removing any portion of the walls of the orbit. 
These consist of the orbicularis palpebrarum, corrugator sn- 
percilii, and tensor tarsi muscles; the eyebrows, eyelashes, 
tarsal cartilages, Meibomian glands, conjunctiva, caruncula 
lachrymalis, lachrymal gland and ducts, puncta lachrymalia, 
lachrymal canals and sac, and nasal duct. 

The integument in this region should, be removed by cut- 
ting in the direction of the fibres of the orbicularis, but in 
the first place the eyelids should be made tense by inserting 
beneath them cotton or tow, and then stitching their edges 
together. 

The EYEBEOWjFig. 4 (i), on each side, is situated just above 

the attached border of the 



Fig. 4. 




upper eyelid, and rests on 
the superciliary ridge of the 
frontal bone. It is gener- 
ally arched and covered 
with hairs, which have a 
direction from within out- 
wards. The integument is 
separated from the orbicu- 
laris and occipito-frontalis 
muscles by a thick, dense 
cellulo-adipose layer. The 
eyebrows can be moved 
upwards, downwards, or 
towards each other. 



a Front View of the Left Eye, mode- 
rately opened. — 1 The supercilia. 2. The 
cilia of each eyelid. 3. The inferior palpe- 
bra. 4. The internal canthus. 5. The ex- 
ternal canthus. 6. The caruncula lachry- 
malis. 7. The plica semilunaris. 8. The 
eyeball. 9. The pupil. 

4 (2), consist of three or 
four rows of curved hairs, growing from the free borders of 



The Eyelashes, Fig. 



APPENDAGES OF EYE OUTSIDE OF ORBIT. 41 

the eyelids. In tlie upper eyelid they are curved upwards, 
in the lower, downwards ; they are longer in the centre than 
at the extremities of the eyelids. Their bulbs are situated 
between the orbicularis and the tarsal cartilages. 

The Orbicularis Palpebrarum, Fig. 61 (7), entirely 
surrounds the fissure between the eyelids. It is divided 
into three portions, viz: the orbicular, the palpebral, and 
the ciliary. The orhicular is spread out around the base of 
the orbit, and rests, above, on the superciliary ridge and 
corrugator supercilii muscle; on the outside, on the tem- 
poral aponeurosis, and below, on the malar bone and zygo- 
maticus major and levator labii superioris muscles; its fibres 
are red and well marked, ^^q palpebral and ciliary portions 
consist of a thin layer of pale fibres situated in the eyelids ; 
the latter lies next to their free borders, and is somewhat 
thicker than the former. This muscle arises from the inter- 
nal angular process of the frontal bone, the nasal process of 
the superior maxilla, and from the upper and lower border 
of the tendo-palpebrarum ; from this narrow attachment the 
fibres proceed outwards, so as to embrace the base of the 
orbit and the fissure between the eyelids. It closes the eye- 
lids, as in winking, principally by depressing the upper 
one ; this is done by the palpebral and ciliary fibres, which 
are involuntary in their action. It also presses the eyelids 
against the ball of the eye, and directs the tears towards the 
puncta lachrymalia. As its principal attachment is at the 
inner canthus of the eye, it draws the integument in that 
direction, and that above the orbit more than that below. 
It is separated in the eyelids from the skin by loose areolar 
tissue, which is very liable to serous infiltration. 

The Tendo-Palpebrarum, or Ligamentum Palpebra- 
rum, arises from the nasal process of the superior maxilla in 
front of the lachrymal groove, passes outwards and back- 
wards to the inner angle of the eyelids, where it divides 
into two parts, one to be attached to the upper, and the other 
to the lower tarsal cartilage. It is about two lines and a 
half in length, and crosses the lachrymal sac a little above its 
centre ; its broadest diameter is at first vertical and then 
horizontal ; from its upper and lower borders a fibrous lamina 
is reflected over the lachrymal sac, and is attached to the 
osseous margin which surrounds it. When the orbicularis 



42 



DISSECTION OF THE HEAD AND NECK. 



contracts, tliis tendon can be felt in tlie living subject. In 
opening the lachrymal sac, the incision should be made below 
the tendon, to avoid injuring it. 

The CoERUGATOE SuPEECiLii, Fig. 64 (2), is exposed by- 
reflecting downwards the upper portion of the orbicularis. 
It arises from the inner part of the superciliary ridge, passes 
upwards and outwards, and is inserted into the orbicularis, 
near the junction of its middle and outer thirds. The super- 
cilii muscles depress and approximate the eyebrows, pro- 
ducing the vertical Avr inkles on the forehead. The expression 
of frowning depends on the action of these muscles. 

The Tensoe Taesi, or The Muscle of Hoenee, Fig. 5, 
arises from the upper part of the os unguis just behind the 
lachrymal groove ; it is about three lines in breadth and 
six in length, and is situated behind the tendo -palpebrarum. 

It divides into two slips, 
which are inserted^ one into 
the upper lachrymal duct, 
and the other into the lower. 
To expose this muscle the 
eyelids should be detached, 
except at the inner can- 
thus, and reflected over the 
nose ; its fibres will then be 
distinctly seen by the re- 
moval of a portion of the 
conjunctiva and areolar tis- 
sue between the eyeball and 
the lachrymal bone. Its 
action is to govern the po- 
sition of the puncta lachry- 
malia, so as to facilitate the entrance of the tears, and to 
keep the eyelids applied to the eyeball ; it may also com- 
press the lachrymal sac if distended.-^ 

The :Meibomian Glands, Fig. 6 (e), consist of a series of 
tubes, more or less tortuous, situated in grooves on the pos- 
terior surface of the tarsal cartilages. In length they cor- 

1 A small muscle, situated in the outer part of the orbit, and connected to 
the tarsal cartilages, is described by Dr. N. R. Mosely, of Philadelphia, in 
the Boston Medical and Surgical Journal, August 3, 1853. Dr. Mosely reo-ards 
it as an antagonistic muscle of the tensor tarsi of Horner. *^ 




A View of the Tensor Tarsi Mus- 
cle. — 1, 1. Bony margins of the orbit. 
2. Opening between the eyelids. 3. In- 
ternal face of the orbit. 4. Origin of the 
tensor tarsi. 5, 5. Insertion in the neigh- 
borhood of the puncta lachrymalis. 



APPENDAGES OF EYE OUTSIDE OF OEBIT. 



43 



respond to tlie breadtTi of tlie cartilages. There are "between 
tliirty and forty in the upper lid, and about twenty in the 
lower. Each tube has opening into it on each side several 
small pouches or follicles. Their external orifices may be 
seen on the posterior edge of the free border of each lid, 
and from which a waxy secretion may be pressed ; this se- 
cretion prevents the tears from flowing over the lids. 

Fig. 6. 




Meibomian Glands, seen from the inner or ocular surface of the eye- 
lids, WITH THE Lachrymal Gland — the left side. a. Palpebral conjunctiva. 
1. Lachrymal gland. 2. Openings of lachrymal ducts. 3. Lachrymal puneta. 
6. Meibomian glands. 

The Tarsal Cartilages, with their fibrous attachments, 
form the framework of the eyelids. They consist of two 
fibro-cartilaginous plates, one for each lid. Each one pre- 
sents two surfaces and two borders. The external surface 
of each is convex, and separated from the ciliary fibres of 
the orbicularis palpebrarum by a thin layer of areolar tissue ; 
the internal surface is concave, and grooved for the Mei- 
bomian glands, and separated from the conjunctiva by areolar 
tissue also. The free borders are thick, and form the free 
edges of the eyelids ; they are nearly horizontal when the 
lids are closed, and slightly beveled from before backwards, 
so as to form, when they are in apposition, a canal for the 
passage of the tears from the outer to the inner part of the 
eyeball. The lower one is merely a narrow band, about a 
line and a half in breadth. The upper one is nearly half an 
inch broad at its centre, but diminishes in breadth towards 



44 DISSECTION OF THE HEAD AND NECK. 

its extremities. Each one is attached to the margin of the 
orbit by a fibrous lamina^ which is continuous with the pe- 
riosteum. This fibrous layer, sometimes called the palpebral 
or broad tarsal ligament^ is thin at the inner part of the 
orbit, but quite thick and dense at the outer part. Besides 
the fibrous layer from the margin of the orbit, the tarsal 
cartilage of the upper lid has inserted into it the tendon of 
the levator palpebrse superioris muscle. The internal extre- 
mities of the tarsal cartilages are fixed by the tendo-palpe- 
brarum. 

The Caruncula Lachey:malis, Eig. 4 (e), is a small red 
body situated at the inner angle of the eyelids, and in the 
centre of the lacus lachrymalis. It is composed of sebaceous 
follicles resembling the Meibomian glands. It secretes a 
whitish substance, which is often seen at the inner canthus. 
It is covered by a fold of the conjunctiva, which is per- 
forated by the external orifices of the follicles ; several hairs 
usually project from it. It varies in color, as in health and 
in sickness. 

The Conjunctiva is divided into an ocular and 2^, palpebral 
portion. The former covers the anterior third of the eye- 
ball, with which it is loosely connected around its circum- 
ference, but becomes more closely adherent as it approaches 
the margin of the cornea. That it extends over the cornea 
can be very satisfactorily demonstrated. It is, however, so 
modified in its structure as to become perfectly transparent, 
and so intimately blended with the cornea, that it cannot be 
easily dissected off, especially from the centre of it The 
latter, or palpebral portion, lines the internal surfaces of the 
lids, and is continuous over their free margins with the skin. 
It is closely connected to the posterior surfaces of the tarsal 
cartilages, where it covers the Meibomian glands, and is very 
vascular. 

The palpebral sinuses are formed by the reflection of the 
conjunctiva from the globe of the eye to the lids. In these 
sinuses, or culs-de-sac, it is very loosely connected to the 
areolar tissue beneath. At the inner canthus the conjunc- 
tiva forms a fold, called the plica semilunaris. This is just 
outside the caruncula, and disappears when the globe is 
turned outwards ; it may be regarded as the rudiment of 



APPENDAGES OF EYE OUTSIDE OF ORBIT. 45 

tlie membrana nictitans or the third eyelid in birds. The 
conjunctiva is perforated by the lachrymal ducts in the 
outer part of the superior palpebral sinus; by the Meibomian 
glands, along the inner edge of the lids; by the sebaceous 
follicles in the caruncula lachrymalis; and by the puncta 
lachrymalia near the inner extremities of the eyelids. 

The Lachrymal GtLANd, Fig. 6{i\ may now be exposed in 
the upper and outer part of the orbit. It should be studied 
from without and also from within the orbit. In structure it 
resembles the salivary glands. It consists of two lobes, an 
orbital and a ^yalpehral. The former is about half an inch 
in breadth, and nearly three-fourths of an inch in length ; its 
orbital surface is convex, and occupies the lachrymal fossa 
on the inner side of the external angular process of the 
frontal bone; its ocular surface is concave, and in apposition 
with the globe of the eye. The latter or palpebral lobe is 
prolonged into the upper lid as far as the attached border of 
the tarsal cartilage ; its under surface is covered by the con- 
junctiva, through which it can be seen when the lid is 
everted. The two lobes are separated from each other 
merely by fascia. The tears secreted by the lachrymal 
gland are poured upon the conjunctiva through from six to 
ten ducts; these are arranged in a line, and open on the 
inner surface of the upper lid. They may be detected by 
the application of a colored liquid, which will be absorbed 
into their mouths. 

The Puncta Lachrymalia, Fig. 6(3), are two orifices, one 
in the free border of each eyelid at the inner extremity of the 
tarsal cartilage. They may be distinctly seen in the centre 
of two small eminences called the lachrymal papillm. They 
look somewhat backwards towards the eyeball, in which posi- 
tion they are kept by the tensor tarsi muscle. A bristle can 
be readily introduced into them, and through them into the 
ducts which lead into the lachrymal sac. 

The Lachrymal Canals, or Canaliculi Lachrymales, 
Fig. 7, e, extend from the puncta to the lachrymal sac. Their 
parietes are of a dense fibrous structure, which keeps them 
constantly open for the passage of the tears. The inferior 
one is th6 shortest ; it at first descends, then turns inwards 
and iipwards to enter the upper and outer part of the sac. 
The superior one is at first directed upwards, then inwards 



46 



DISSECTION OF THE HEAD AND XECK. 



and downwards, and enters tlie sac near the other, 'beMnd the 
tendon of the orbicularis. 

The Lachey:mal Sac occupies a fossa formed by the su- 
perior maxilla and os unguis in the inner and anterior part 
of the orbit. It is continuous with the upper extremity of 
the ductus ad nasum, from which it is separated only by a 
constriction or fold of the mucous membrane. It is separated 
from the anterior extremity of the middle meatus of the nose 
by the lachrymal bone. 

The Ductus ad I^asum, Fig. 7, /, leads from the lachrymal 
sac into the anterior extremity of the inferior meatus of the 

Fig. 7. 




Lachrymal Apparatus ant) Xasal Duct.— ct, h, c. Lachrymal gland and its 
appendage^ <i. Puncta lachrymalia. e. Lachrymal canals. /. Xasal duct laid 
open. g. Insertion of tendon of superior oblique muscle after being reflected, h. 
Supra-orbital foramen: the artery, vein, and nerve have been cut across, i. Inte- 
rior of nasal duct near its termination in nostril. 

nose. It is directed downwards, backwards, and outwards ; 
its osseous walls are composed of the superior maxilla, os 
unguis, and inferior turbinated bone. At is lower orifice there 
is a fold of mucous membrane which may serye as a yalye. 
Its leugth is about three-fourths of an inch. Through the 



SOFT PARTS ON THE UPPER PART OF CRANIUM. 47 

lachrymal ducts, lachrymal sac, and nasal duct, the conjunc- 
tiva is continuous with the lining membrane of the nasal 
fossa; and as the former is prolonged into the lachrymal gland 
through its excretory ducts, there is a direct sympathetic 
connection established between that gland and the mucous 
membrane of the nose. 

The appendages of the eye, which have just been described, 
deserve the careful attention of the student. They are fre- 
quently the seat of diseases which require surgical operations. 
A minute examination of the structure of the eyelids, and the 
lachrymal passages especially, is important. 



Sect. III. — Dissection of the soft parts on the upper 

PART OF THE CrANIUM. 

This region is included within the circumference of a line 
commencing just above the root of the nose, and extending 
round the head through the eyebrows, along the zygomatic 
arches, and just above the ears back to the occipital protuber- 
ance. It is subdivided into the Frontal, Temporal, Auricular, 
and Occipital regions. The parts to be studied in this dissec- 
tion are: the integuments, the cellulo-adipose layer, the tem- 
poral fascia, the occipito -frontal muscle, the upper part of the 
orbicularis palpebrarum, the temporal muscle above the zygo- 
matic arch, the attollens aurem, the attrahens aurem, the retra- 
hens aurem, the cranial branches of the occipital, temporal, 
auricular, supra-orbital and facial arteries, and their corres- 
ponding veins, the cranial branches of the occipital, facial, and 
trifacial nerves, and the pericranium. 

In removing the skin, an incision should be made from the 
root of the nose along the median line to the occipital pro- 
tuberance, and another at right angles to this, extending down 
to the ear. The skin should then be dissected off' in two flaps. 
The different layers which cover the cranium should be dis- 
sected on one side, and the nerves and vessels on the other. 
The integument which is covered with hair adheres closely to 
the cellulo-adipose layer, and some care is requisite to separ- 
ate them. 

The Cellulo-adipose Layer is the tliickest and most 
dense on the upper and posterior part of the head. Numerous 



48 DISSECTION OF THE HEAD AND NECK. 

adipose cells are interspersed throngli it. The compactness 
of this structure, with its high degree of vitality, is said to be 
the cause of the tendency of the scalp to take on erysipelatous 
inflammation after injuries. When arteries are divided in its 
substance, the forceps instead of the tenaculum should be 
used in ligating them. 

The OCCIPITO-FEONTAL MuSCLE, Fig. 61 (i, 2, s), with its 
broad aponeurosis, extends from the root of the nose and the 
superciliary ridge to the superior transverse ridge of the 
occiput. It consists of two fleshy bellies connected by a broad 
aponeurosis, which expands over the arch of the cranium. 

The OCCIPITAL POETION arises from the superior transverse 
ridge of the occipital bone, and from the adjacent portion of 
the mastoid process of the temporal bone. The fibres pass 
upwards and somewhat inwards-, and terminate in the tendon. 

The FEONTAL POETION is blended with the pyramidalis 
nasi, the orbicularis palpebrarum, and the integument ; some 
of its fibres are also attached to the internal angular process 
of the frontal bone. It joins the tendon nearly opposite the 
coronal suture. Its fibres are generally paler than those of 
the occipital portion. The tendon of this muscle is continu- 
ous across the median line with that of the opposite side ; and 
from its outer border, the superficial temporal fascia extends 
downwards over the deep temporal fascia or aponeurosis. 
The use of this muscle is to move the scalp, to raise the eye- 
brows, and, in some measure, the upper eyelids. It adheres 
closely to the scalp, while it glides freely on the parts beneath 
it. It causes the transverse wrinkles on the forehead. 

The Attollens Aueem, Fig. 61 (4), is situated in the tem- 
poral region above the ear. It arises iDroad from the aponeu- 
rosis of the occipito -frontal muscle ; its fibres converge as they 
descend, and are inserted into the concha of the ear. Its use 
is to raise the ear, and to render tense the aponeurosis from 
which it arises. 

_ ^The Attrahens Aueem, Fig. 61 (3), is situated immediately 
in front of the preceding muscle. It arises from the aponeu- 
rosis of the occipito-frontal muscle and the zygoma, and is 
inserted into the anterior part of the helix. It cfraws' the ear 
upwards and forwards. 



SOFT PARTS ON THE UPPER PART OF CRANIUM. 49 

The Ketrahens Aurem, Fig. 61 (e), is placed behind the ear. 
It generally consists of two or three fasciculi. It arises from 
the mastoid process, and is inserted into the posterior and lower 
part of the concha. It draws the ear backwards and enlarges 
the meatus. Having dissected the occipito-frontal muscle and 
the muscles of the ear, thej should be removed. Beneath 
the occipito-frontal muscle, more or less loose areolar tissue 
Avill be observed, which facilitates the movements of that 
muscle on the pericranium. The jpericranium is the external 
periosteum of the bones which it covers. It can be readily 
separated from the bone except along the sutures. 

The student should now carefully study the different layers 
which have just been examined with reference to wounds 
involving one or more of them, and especially in view of 
collections of pus between the different layers, or beneath the 
pericranium. 

The Temporal Aponeurosis occupies the whole of 
the temporal region. It arises from the temporal ridge 
above, and is attached below to the zygomatic arch. The 
lower part of it is divided into two layers, one of which is 
inserted into the outer, and the other into the inner border 
of the arch, thus leaving a triangular space between them, 
which is filled with adipose substance, and traversed by the 
middle temporal artery, and a small branch of the superior 
maxillary nerve. The temporal muscle arises partly from 
the under surface of this aponeurosis. It will be observed, 
that if pus should collect beneath the temporal aponeurosis, 
it would naturally seek an outlet beneath the zygomatic 
arch ; or, if it should collect between the two layers above 
the zygoma, it would necessarily be confined to that space. 

The Temporal Muscle, Fig. 64 (i), lies beneath the tem- 
poral aponeurosis. It arises from the whole of the temporal 
fossa and ridge, from the inner surface of the aponeurosis 
and from the zygomatic arch. Its fibres converge, and 
passing downwards beneath the zygoma, are inserted by 
a strong tendon into the coronoid process of the inferior 
maxilla. The muscle increases in thickness as it descends. 
When the entire muscle acts, it raises the lower jaw; the 
posterior fibres can move it backwards, Avhile the anterior 
fibres can draw it forwards. This muscle may also assist in 
producing a rotary movement of the jaw. 
5 



50 DISSECTION OF THE HEAD AND NECK. 

It will be seen tliat tlie temporal aponeurosis and muscle, 
by their strength and thickness, serve greatly to protect that 
portion of the parietes of the cranium which they cover, and 
which in this region are very thin. 

The vessels and nerves may now be dissected on the oppo- 
site side; and for this purpose, the integument should be 
raised in the same manner as for the dissection of the muscles 
and fasciae. 

The temporal and occipital, Fig. 1 (2 3, 20), are the principal 
arteries. Besides these, there are the terminal branches of the 
facial, the supra- orbital, and the posterior auricular. The 
nerves. Fig. 68, are derived from the fifth, the facial, and the 
cervical. To dissect the vessels and nerves, they should be 
traced from below upwards. 

Entering the frontal region from below will be found the 
terminal branch of the facial artery, and the supra-orbital, 
and near these the supra-orbital and frontal nerves. 

The SuPEA-OEBiTAL Arteey and Keeye pass through 
the supra-orbital foramen. The artery is distributed to 
the muscles and integument of this region. The nerve 
ascends beneath the orbicularis palpebrarum and occipito- 
frontal muscles, and some distance above the orbit divides 
into two cutaneous branches, which perforate the latter 
muscle, and ascend in long slender filaments to the top of 
the head. Id its course it gives branches to the muscles 
beneath which it passes, and through which filaments are 
sent to the skin which covers the muscles. 

The terminal branch of the Facial Aeteey supplies the 
parts above the root of the nose. 

The Feontal Neeve is placed on the inner side of the 
supra-orbital, and has a similar course and distribution. 

Besides the supra-orbital, the Ophthalmic Aeteey usually 
sends one or more small branches to the forehead. 

The Tempoeal Aeteey passes upwards over the zygoma, 
and close to the ear. It is accompanied by the auriculo- 
temporal branch of the inferior maxillary division of the 
fifth pair of nerves. It divides into an anterior and a poste- 
rior branch. Just above the zygoma it gives off the middle 
temporal branch, which perforates the temporal aponeurosis. 



SOFT PARTS ON THE UPPER PART OF CRANIUM. 51 

The anterior division pursues a tortuous course upwards and 
forwards to the upper part of the forehead. The posterior 
division passes upwards and backwards to the upper and 
back part of the head. The lower part of this artery should 
never be opened for the abstraction of blood, on account of its 
depth and the danger of ecchymosis occurring. The anterior 
division is superficial, and easily found on the forehead. 

The Nerves in this region are a small branch of the 
superior maxillary^ the auricuh-temporal branch of the infe- 
rior maxillary, and branches of the facial nerve. 

The first one perforates the temporal aponeurosis just above 
the zygoma. The auriculo-temporal divides into branches, 
which ascend to the top of the head. It also sends filaments 
to the upper part of the ear, to the retrahens aurem, and to 
the integument above the ear. The branches of the facial 
nerve pass up over the zygoma, and ramify in the temporal 
and frontal regions, anastomosing with the branches of the 
fifth pair. 

The Posterior Auricular Artery, Fig. 1 (21), ascends 
between the mastoid process and the ear. It sends branches 
to the ear, to the integument behind the ear, and to the occipito- 
frontal muscle and the retrahens aurem. The posterior auricu- 
lar branch of the facial nerve, and the deep auricular branch 
of the auricularis magnus, are found in this region. — 
The former passes upwards over the anterior and outer sur- 
face of the mastoid process, and divides into an ascending 
and a horizontal branch. The ascending branch supplies the 
retrahens aurem, and the attoUens aurem ; the horizontal 
branch is distributed to the occipito-frontal muscle. The 
latter ascends at first in front of the mastoid process, and 
then behind the retrahens aurem. It divides into an anterior 
and a posterior branch, which are distributed to the skin. 

The Occipital Artery becomes superficial at the inner 
border of the splenius muscle. It then ascends on the back 
part of the head, ramifying in the scalp, and anastomosing 
with the posterior auricular, the temporal, and the corres- 
ponding one on the opposite side. 

The nerves in this region are the Occipitalis Ifajor and 
the Occipitalis Minor. Tlio former perforates the trapezius 
muscle, and accompanies the occipital artery. The latter 
ascends on the inner border of the mastoid muscle, and rami- 



52 DISSECTION OF THE HEAD AND NECK. 

fies on the back of the head, between the auricular and the 
great occipital nerves. 

The Superficial Veins, Fig. 62, of the head correspond 
generally to the arteries. Those which pass through the 
foramina in the parietal bones are named the emissaries of 
Santorini. They open into the superior longitudinal sinus. 



Sect. IV. — Dissection of the Membranes of the Brain. 

Having dissected the soft parts covering the upper part of 
the cranium, the calvaria may be removed. If it be de- 
sired to preserve the cranium for a preparation, this should 
be done with a saw. The incision should pass through the 
occipital protuberance behind, about half an inch above the 
ear on each side, and just above the superciliary ridges in 
front. The variations in the thickness of the skull ?t differ- 
ent points through which this incision would pass, should be 
observed on one which has already been sawed. It is better 
to divide both tables entirely with the saw, so that but little 
effort will be required afterwards to raise the calvaria from 
the dura mater. This may be done with a chisel, first prying 
up one part and then another, until it has been detached 
around the whole circumference of the incision. If the saw 
be sharp, there mil be but little danger of injuring the brain 
or its membranes, as there will then be no necessity for 
using any force to press it down on the bone. The position of 
the subject should be changed to saw through the anterior 
and posterior portions of the cranium. 

The strength of the adhesions between the upper part of 
the cranium and the dura mater, varies greatly in different 
subjects. Sometimes a good deal of force is required to 
effect a separation, although the bone has been entirely di- 
vided. 

The description of the meninges of the brain will be divided 
into two parts. The first will embrace all the parts which 
can be examined before the removal of the brain ; the second 
will include the deep parts, or those which can be seen only 
after the brain has been removed. 

The membranes of the brain consist of the Dura Mater, 
the Arachnoid, and the Pia Mater. 



OF THE MEMBRANES OF THE BRAIN. 53 

The Dura Mater is a fihro-serous membrane. It adheres 
to the imier surface of the osseous walls of the cranium. It 
is of a dense fibrous structure. Its fibres run in different 
directions, thus imparting to it great strength. In some 
places it separates into two layers, as in the formation of 
sinuses for the transmission of venous blood. The firmness 
of its attachment at different points to the cranium, prevents 
any general displacement of it taking place. Its external 
surface is rough, while its internal surface is smooth, and 
presents the appearance of serous membranes generally. 
Its uses are the following : — 

1. It performs the ofhce of an internal periosteum to the 
bones of the cranium. 2. It furnishes processes to separate 
and support different parts of the encephalon. 8. It sup- 
plies canals or sinuses for conveying venous blood. 4. It 
provides the nerves with fibrous sheaths as they pass through 
the foramina in the base of the cranium. 5. It affords a 
general protection to the brain, especially in early life, before 
the bones of the cranium are yet completely ossified. Its 
intimate connection with the external periosteum will be 
noticed at another time. 

The Arachnoid Tunic is a serous membrane, and, like 
other serous membranes, forms a shut sac ; the reflected 
portion of it, however, is described as a part of the dura 
mater. This membrane, the visceral portion, surrounds every 
part of the encephalon. It adheres quite closely to the pia 
mater, especially immediately over the convolutions, except 
at particular parts on the under surface of the brain. It 
is connected to the reflected portion by an arrangement 
consisting of tubes which allows the vessels and nerves to 
pass to and from the brain without interrupting its continuit}^. 
The ends of each one of these tubes are continuous, the one 
with the reflected portion, and the other with the viscei-al 
portion. 

The Pia Mater is a vascular membrane. It invests every 
part of the exterior of the encephalon, dips in between the 
convolutions, and also lines the ventricles. It is intimately 
connected with the substance of the brain by vessels and 
prolongations of areolar tissue. 

With these general remarks on the meninges of the brain, 
the student will be prepared to connnence the examination 

5^ 



54 DISSECTION OF THE HEAD AND NECK. 

of them in situ, and as thej will appear from time to time in 
the progress of his dissection. 

On the inner surface of the calvaria will be observed a 
groove extending along the median line ; this corresponds to 
the superior longitudinal sinus. On each side di^TQ furrows 
which present in their arrangement an arborescent appear- 
ance; these are occupied by branches of the middle meningeal 
artery. Small depressions on either side of the median line 
are commonly seen ; these are for the lodgement of the exter- 
nal glands of Pacchioni. 

On the external surface of the dura mater, the situation of 
the superior longitudinal sinus, the ramifications of the middle 
meningeal artery, and the external glands of Pacchioni, will 
be noticed. The dura mater is usually studded with points 
of blood caused by the rupture of vessels in the removal of 
the calvaria. 

The SuPERioK Longitudinal Sinus, Fig. 8, 5, may now 
be laid open, and any coagulated blood which it may contain, 




A ^ lEW OP THE Sinuses op the Dura Mater.— n. The toreular Herophili. h 
The superior longitudinal sinus, c. The inferior longitudinal sinus, d. The strai<^ht 
sinus, e. The venae Galeni. /. The lateral sinus of the left side. a. The postenor 
occipital sinus, h The superior petrosal sinus. ^. The inferior petrosal sinus. ]c 
The internal nasal veins. 

washed out. It commences at the foramen caecum, and extends 
to the toreular Herophili, Fig. 8, a; increasing in size from 
Its commencement to its termination. When cut transversely 
It presents a triangular figure, with the apex directed down- 



OF THE MEMBRANES OF THE BRAIN. 55 

wards. The middle glands of Pacchioni are situated in it; 
often these are very small or entirely absent. The mouths 
of the veins of the pia mater will be seen opening into it. 
Fibrous bands stretch across it; they are called the chordm 
Willisii. These cords, however, are not very distinct. The 
superior longitudinal sinus receives blood from the nose and 
frontal sinus, from the diploe, pericranium, and dura mater, 
as well as from the veins of the pia mater. 

An incision should now be made through the dura mater 
corresponding to the one made in the bone for removing the 
calvaria. Kaising it up on each side from the arachnoid, 
its serous surface will be observed, and, tracing it towards the 
median line, it will be found to be reflected down between 
the two hemispheres of the brain. This reflected or vertical 
portion is the/a/x cerebri. Before raising the falx, it will be 
necessary to divide the veins of the pia mater. It will be 
observed that many of these enter the longitudinal sinus in 
a direction from behind forwards; this arrangement has a 
tendency to prevent these veins being too rapidly emptied, 
which would be liable to cause syncope. The internal glands 
of Pacchioni are found on the inner surface of the dura 
mater, near the longitudinal sinus. 

By separating the hemispheres a short distance, the falx, 
Fig. 9 (3), can be seen in situ. Its lower border is concave, 
and corresponds to the upper surface of the corpus callosum, 
which it nearly touches behind. It is attached anteriorly to 
the crista galli, and posteriorly to the tentorium ; its anterior 
extremity is quite narrow, while its posterior extremity is 
broad. The inferior or concave border contains the inferior 
longitudinal sinus, Fig. 8, c, which resembles in its form an 
ordinary vein. The falx may be divided just above its ante- 
rior attachment, and turned backwards out of the way for 
the present. 

The upper part of the cerebrum is now covered by the 
arachnoid and pia mater, through which the convolutions 
are clearly seen. The size and direction of the veins of the 
pia mater may be noticed. On separating the hemispheres, 
the arachnoid will be seen reflected from one to the other 
without reaching to the bottom of the Assure. The pia mater 
lines the Assure througliout its whole extent. The arteries 
of the corpus callosum are seen resting on it anteriorly, but 
dividing into branches as they pass backwards. 



56 



DISSECTION OF THE HEAD AND NECK. 
Fig. 9. 




1. Vertical section of the head. 2. The frontal sinus. 3. The falx cerebri. 
4. Its origin from the crista galli. 5. Its attachment along the sagital suture. 6. 
The lower or concave edge of the falx. 7. Its continuation to the tentorium. 8. 
The tentorium. 9. Its attachment to the petrous portion of the temporal bone. 
10. The free edge of the same part. 11. The convolutions of the right anterior 
lobe of the cerebrum. 12. The anterior extremity of the corpus callosum. 13. The 
septum lucidum. 14. Section of the anterior commissure. 15. Anterior crus of the 
fornix. 16. Middle of the fornix. 17. Its posterior extremity joining the corpus 
callosum. 18. Internal side of the thalamus nervi optici. 19. Section of the corpus 
striatum. 20. Lateral parietes of the third ventricle. 21. A portion of the dura mater 
turned off. 22. Section of the internal carotid artery. 



Sect. Y. — Dissection of the Brain. 

By removing a portion of the araclinoid and pi a mater 
above tlie corpus callosum, this body may be inspected before 
any dissection of the brain is made ; its depth from the upper 
surface of the brain, and the distance of its anterior and 
posterior borders from the extremities of the cerebrum, are 
worthy of notice. It is important that the student obtains a 
distinct idea of the situation of this body in relation to the 
periphery of the brain, as it will assist him greatly in learn- 
ing and fixing in his mind the exact location of many other 
parts. It is the great starting point in dissecting the central 
or figurative part of the brain from above downwards. 

Before commencing the dissection of the cerebrum, the 
student may observe the appearance and general arrangement 
of the convolutions of the two hemispheres. The depth of 
the sulci, between the convolutions, is best seen from sec- 



THE CEEEBRUM. 57 

tions of the brain. The convolutions on the two sides do 
not exactly correspond in their direction or nnmber. This, 
however, does not interfere at all with the functions of the 
organ. 

The dissection of tlie brain is begun by making a hori- 
zontal transverse incision through one hemispliere on a level 
with the upper surface of the corpus callosum. In doing this, 
the corpus callosum is kept in view, and answers for a guide. 
The following points are now to be noticed : Just above the 
corpus callosum, and projecting somewhat over it, is a long 
convolution, not only extending the whole length of it, but 
bending downwards both before and behind, to terminate on 
the base of the brain. If the medullary substance in this 
convolution be examined in that portion of the bemispbere 
which has been removed, it will be found to contain longitu- 
dinal fibres. These fibres constitute the superwr longitudinal 
commissure^ and are supposed to connect, physiologically, the 
anterior, middle, and posterior portions of the hemisphere. 

The Corpus Callosum, Fig. 10, is about three inches and 
a half in length. It is arched from before backwards, broader 
behind than before, and thinnest in the middle. Two ridges 
are seen on the upper surface, close to the median line, 
extending from its anterior to its posterior border; these 
ridges are not always parallel to each other. The raphe is 
situated in the median line. The linecE transversce are slight 
elevations extending from the longitudinal ridges to the later- 
al borders ; they indicate the direction of the fibres of which 
the corpus callosum is composed. The termination of the 
corpus callosum, neither anteriorly nor posteriorly, can be 
seen at this stage of the dissection. It may be stated here, 
however, that it passes downwards and backwards, in front, to 
the lamina cinerea, or the anterior part of the floor of the 
third ventricle. Its reflected portion gradually diminishes in 
thickness to its termination. The term govu, or knee, has been 
applied to the junction of the horizontal and reflected por- 
tions, and rostrum to the lower part, just in front of the floor 
of the third ventricle. Posteriorly, it seems to be doubled 
upon itself, the lower or reflected part a})parently terminating 
in the posterior extremity of the fornix, Ibrming the upper 
boundary of the transverse fissure at this point, Laterall}^, 
the fibres of the corpus callosum are lost in the hemispheres. 



58 DISSECTION OF THE HEAD AND NECK. 

The corpus callosum forms the roof of the two lateral veil- 
tricles, and has attached to its under surface, along the median 
line, the septum lucidum. The next thing to be done is to 

Fig. 10. 




A Vertical Section ix the Median Plane, op the Cerebrum, Cerebellum, 
Pons, and Medulla Oblongata — the parts being all represented in their 
natural position. — o. Anterior, and b. Posterior extremity of corpus callosum, 
which is seen in section, d, c, e. Third ventricle, c. Soft commissure, d, e. Thal- 
amus opticus, forming side of third ventricle. /. Fornix, united behind to corpus 
callosum. b, g. Anterior pillars of fornix. Between g and h, anterior commissure. 
Behind h, lamina cinerea. h, h', h". Convolution of corpus callosum or gyrus forni- 
catus. {. Infundibulum. k. Corpora quadrigemina, seen in section, k to I. Valve 
of Vieussens. I. Section of cerebellum, showing white and gray matter — appearance 
named arbor vitae. m. Notch of cerebellum, n. Corpus albicans of right side, 
o. Pons Varolii (section), p. Pituitary body. r. Choroid plexus, s. Septum lu- 
cidum. t. Cerebral peduncle of right side, in section. «. Pineal gland, v. Cavity 
of fourth ventricle, d to v. Iter a tertio ad quartum ventriculum, or aqueduct of 
Sylvius. X, x', x". Marginal convolution of the longitudinal fissure, y. Posterior 
lobe of cerebrum, z. Opening leading into fourth ventricle. 1. Olfactory nerve. 
2. Optic nerve divided through optic commissure. 3. Third nerve, or motor oculi. 

expose the parts beneath the corpus callosum, without in- 
juring them. As the septum lucidum is attached to this body, 
the central part of it must be allowed to remain while the 
lateral portions of it are removed. This can be done by 
making an incision through it on each side of the raphe, and 
about a line from the latter, from near the anterior to the pos- 



THE CEREBRUM. 59 

terior border. Having cut into the ventricles, and observed the 
thickness of the corpus callosum, it may be reflected ontwards 
on each side, or cnt away with the scissors. The incision on 
each side should be extended backwards and outwards for a 
short distance in the direction of the lateral cornu, so as to 
expose more fully the ventricle and its contents. 

The Septum Lucidum, Fig. 10, s, will now be seen forming a 
vertical septum between the two lateral ventricles. By lifting 
up the central portion of the corpus callosum between the 
handles of two scalpels, and placing a light on the opposite 
side, its translucent character will be seen. It has the shape of a 
falx, with its broad extremity situated anteriorly, and its poste- 
rior extremity tapering to a point between the corpus callosum 
and fornix. It consists of two lamella of medullary sub- 
stance, separated by a small space called the fifth ventricle. 

The Fifth Ventricle is situated in the anterior part 
of it; and to demonstrate it, the upper part of the septum 
should be cut away with the scissors. Sometimes the two 
lamellge adhere to each other, and again they are separated 
by a small quantity of fluid. The fifth ventricle does not 
usually communicate with the third ventricle. 

The Lateral Yentricle, Fig. 11, on each side, consists of 
a body and three cornua, one for each lobe of the hemisphere. 
The anterior cornu is the space between the reflected portion 
of the corpus callosum and the anterior extremity of the 
corpus striatum. The examination of the posterior and middle 
cornua may be postponed until the body of the ventricle has 
been studied. The body presents three surfaces: the upper, 
or corpus callosum; the inner, or septum lucidum; and the 
lower, or floor, which is composed of several parts. Of these 
parts, there are five which deserve special notice. They are 
the corpus striatum, taenia semicircularis, thalamus opticus, 
plexus choroides, and fornix. 

The Corpus Striatum, Fig. 11, /i-, forms the outer and an- 
terior part of the floor of the ventricle. It is pear-shaped, with 
the large extremity situated anteriorly, and the small extrem- 
ity posteriorly. It is readily distinguished from the surround- 
ing parts by its dark-grayisli color. It is called the striated 
body, on account of the intermixture of gray and white sub- 
stance in its structure, which gives to it a striated appearance 



60 



DISSECTION OF THE HEAD AND NECK. 



wlien it is cut into. The external portion of tlie brain corre- 
sponding to the corpus striatum is the islmid of Rei\ in the 
fissure of Sylvius. 

The T^nia Semicirculakis, Fig. 11, s, is a narrow, whitish 
band, situated along the inner concave border of the corpus 

Fig. 11. 




Section of Cerebrum, displayixg the Lateral Ventricles. On the right 
SIDE, THE descending Cornu IS LAID OPEN. — a, h. Parts of great longitudinal fissure, 
c. Section of front of corpus callosum. d. Part of posterior end of the same. /. The 
body of the fornix, e. The left choroid plexus, g. Anterior cornu, A., posterior, and 
5, descending cornu of the lateral ventricle, h, h. Corpora striata. I, I. Optic thai- 
ami, n, n. Right and left hippocampus minor, o. Posterior pillar of fornix, be- 
coming continued as the corpus fimbriatum, v. q. Cornu Ammonis, or Pes hippocampi, 
r. Shows alternate gray and white layers in cortical substance, s, s. Right and left 
taenia semicircularis. v. Corpus fimbriatum. y. Eminentia collateralis. 

striatum. It extends from the anterior cornu of the fornix 
to the posterior part of the thalamus opticus, where it is con- 
nected to the corpus geniculatum externum. 

The Thalamus Nervi Opticl, Fig. 11, ?, is seen on the 
inner side of the t^nia semicircularis, by which it is separated 
from the posterior part of the corpus striatum. It is white, 



THE CEEEBEUM. 61 

and only a small portion of it is seen in the floor of the 
lateral ventricle. 

The Plexus Chokoides, Fig. 11, e, is composed of vessels 
and areolar tissue, being a portion of the pia mater. It is 
situated on the inner side of the thalamus. It is red in the 
recent brain. 

The FoENix, Fig. 11,/ is a white body forming the inner 
part of the floor. Anteriorly, it is connected with the septum 
lucidum; and posteriorly, with the corpus callosum. 

Besides these five bodies, the student may notice along the 
concave border of the corpus striatum a narrow, shining 
band, called the Lamina Cornea. This is apparently a 
thickening of the lining membrane of the ventricle. It is 
not always very distinct. Beneath this is a vein of consider- 
able size, coming from the corpus striatum. The floors of the 
two lateral ventricles are perfectly symmetrical. 

The PosTEEiOE CoENU of the lateral ventricle. Fig. 11, 7i, 
is an extension into the posterior lobe. It proceeds outwards 
at first, and then inwards. Its floor is formed by a spur- 
shaped elevation called the Hippocampus Minoe. The upper 
and lateral walls consist of white medullary substance. 

The Middle or Infeeioe Coenu, Fig. 11, g, is much larger. 
It curves outwards, downwards, and forwards around the 
posterior, outer and lower part of the thalamus. This cavity 
may be exposed by removing the tipper and outer portion 
of the middle lobe down to a level with it ; or it may be 
fully brought into view by making a single incision, cutting 
from within outwards, and following the course of the cornu 
from its commencement to its termination, and then lifting 
up that portion of the middle lobe situated above it. The 
following parts are found in the middle cornu. 

. ^hQ plexus choroides extends into the middle cornu, and dis- 
appears there, by becoming continuous with the pia mater in 
the transverse fissure ; this must be removed to expose the 
parts beneath it. 

The Hippocampus Majoe extends the whole length of the 
floor, and terminates in an indented expansion, called the 
pes hippocampi. This body follows the curved direction of 
the cavity; presents a smooth Avhito ap}K\irauco, convex ex- 



62 



DISSECTIOX OF THE HEAD AXD XECK. 



temally and concave internally. Tliis body is formed by 
the posterior and reflected portion of the convolntion wliich 
was seen on the inner side of the hemisphere, immediately 
above the corpus callosnm; it has a corresponding depres- 
sion or sulcus on the base of the brain. 

The T-EXiA Hippocampi, or Coepus Fimbeiatuai, is a nar- 
row white band occupying the concave border of the hippo- 

Fiff. 12. 




A Section of the Cerebral HEiiisPHEEES, sho'^ing both lateral textri- 

CLES, AFTER THE FOR^ax HAS BEEX DITIDED AXD TrRN'ED BACK, TO EXPOSE THE 

VELrJi iXTERPOSiTUii. — c. The anterior portion of corpus callosum, cut across, e. 
The lyra, or under surface of posterior part of corpus callosum. f. Anterior pillars 
of fornix cut across. X. B. These are represented of too great size. g. Anterior, 
h, posterior cornu of lateral ventricle. /.-, J:. Corpora striata, q. Pes hippocampi. 
r, r. Thalami optici. s, s. Taenia semicircularis. t, t. Choroid plexuses, v. Telum 
interpositum. .r, x. Posterior pillars of fornix, ij. Eminentia collateralis. 

campus major; it is a continuation of the posterior pillar of 
the fornix; its concave border is free, while its convex mar- 
gin can usually be raised only slightly from the hippocampus. 



THE CEREBRUM. 63 

Wlien the free border of the corpus fimbriatum is raised up 
and turned over on the hippocampus, the corpus deisttatum 
is brought into view. It is a reddish gray body, serrated, 
and lies within the concavity of the hippocampus. 

The internal and upper wall of the middle cornu is formed 
by the thalamus opticus and corpus striatum. On the lower 
and posterior part of the thalamus may be observed two 
small bodies, the corpus geniculatum,^ externum and inter- 
num. The latter is located a little anterior to and below 
the former ; it is also somewhat smaller, and of a paler ap- 
pearance. These bodies are connected by white bands to 
the tubercula quadrigemina. The optic nerve arises in part 
from them. 

Having observed the walls and contents of the lateral 
ventricles, the stu.dent may proceed with the dissection in 
the direction of the third ventricle. 

This ventricle is situated under the fornix, which has not 
as yet been disturbed. By observing the point at which 
the plexus choroides on each side passes beneath the fornix, 
the position of the foramen of Monroe will be found, as it is 
occupied by the junction of the two plexuses. This foramen 
forms the only direct communication between the lateral 
ventricles, and also between them and the third ventricle. 

Now divide the fornix over the foramen of Monroe, and 
carefully raise up and reflect one portion forwards and the 
other backwards. The union of the two plexuses will now 
be seen, and also a thin delicate membrane stretching across 
from one plexus to the other, and which lined the inferior 
surface of the fornix behind the foramen of Monroe ; this is 
called the velum interpositum^ Fig. 12, v. The handle of the 
scalpel should now be carried backwards between the fornix 
and the velum interpositum, separating the latter from the 
former, and also from the posterior border of the corpus 
callosu.m. On the under su.rface of the posterior part of the 
corpus callosum, and between the posterior pillars of the 
fornix, are several oblique lines, which constitute what is 
called the lyra^ Fig. 12, e. By dividing what remains of the 
posterior part of the corpus callosum and fornix, in the 
direction of the median line, the connection between these 
two bodies may be examined ; also the manner in which the 
fornix is connected on the sides with the two hippocampi and 
the corpora fimbriata. These last connections Ibrm the postc- 



64 DISSECTION OF THE HEAD AND NECK. 

rior pillars^ or crura^ Fig. 12, x^ cc, of tTie fornix, of wlaicli there 
is one on each side. It will be observed that the borders of 
the central part of the fornix are entirely free, resting upon 
the plexuses and the velum interpositum. The anterior part 
of the fornix divides into two crura, which pass downwards 
towards the base of the brain. These will be seen more 
distinctly when the third ventricle is fairly exposed. 

The velum interpositum may now be raised and reflected 
backwards, observing, at the same time, two veins, the vence 
Galeni^ Fig. 8, e, occupying the centre of it. These veins col- 
lect the blood from the different bodies in the ventricles and 
convey it into the sinus rectus. In separating the pia mater 
from the substance of the brain, care should always be taken 
to divide with the scalpel or scissors any small vessels which 
are not readily broken. In raising the posterior part of the 
velum, it should be borne in mind that it is closely connected 
to the pineal gland, and that this part of it, therefore, should 
be dissected, and not torn away. With a little care, and by 
using the forceps and scissors, the student Avill be able to 
preserve this small body with its connections to the thalami 
and posterior commissure of the third ventricle. 

The Thied Yentkicle, Fig. 13, z to s, should now be exam- 
ined. It is located between the thalami nervorum opticorum 
and below the fornix and velum interpositum ; the locus per- 
foratus medius, eminentise mammillares, and tuber cinereum, 
which are seen on the base of the brain, are placed imm.e- 
diately below it. It contains three commissures, an anterior^ 
a middle, and a posterior. The middle one is not a true com- 
missure; it consists of gray substance, formed apparently 
by a mere adhesion of the two thalami. It is apt to be 
broken away in separating the bodies to expose the other 
parts in the ventricle. It is sometimes absent. In the ante- 
rior part of the ventricle are seen, first, the anterior crura of 
the fornix, having a vertical direction ; second, in front of, and 
between these, the anterior commissure, a small transverse 
cylindrical body connecting the corpora striata and the con- 
volutions of the middle lobes; and third, below this, and 
between the crura, the opening which leads into the infundib- 
ulum. In the posterior part are observed, first, the peduncles 
of the pineal gland, which extend forwards along the inner 
margins of the thalami, to Avhich they adhere, to connect 
with the anterior crura of the fornix and the taenia semi- 



THE CEREBRUM. 65 

circular es ; second, the posterior commissure^ a white, cylindri- 
cal body, which connects the two thalami; third, just beneath 
this, the aqueduct of Sylvius^ or the opening which leads to 
the fourth ventricle. The floor of the third ventricle is only 

Fig. 13. 




Section of the Cerebrum displaying the Surfaces of the Corpora Striata, 
AND Optic Thalami, the Cavity op the Third Ventricle, and the Upper Sur- 
face OF THE Cerebellum. — a, e. Tubercula quadrigcmiriii — c, testis, a, nates, c. Cor- 
pus callosum. /. Anterior pillars of fornix. 7. Anterior cornu of lateral ventricle. 
/(•, h. Corpora striata. I, I. Optic thalami. * Anterior tubercle of the left thnlainns. 
z to s. Third ventricle. In front of z, anterior coniinissure. h. Soft comniissuro. 
s. Posterior commissure, p. Pineal gland with its peduncles, n, n. Processus cere- 
belli ad testes, in, m. Ileraispheres of the cerebellum, h. Superior vermiforui 
process, i. Notch behind the cerebellum. 

about a line in thickness, so that tliis cavity is situated very 
near to the basilar surficc of the brain. 

The Pineal Gland, Fig. 13, }\ has ah-eady been exposed. 
It is of a pyriforni shape, with its base turned forwards and 
upwards, and consists of gray matter, which contains small, 



6Q DISSECTION OF THE HEAD AND NECK. 

calcareous bodies. It generally contains a small cavity. It 
rests on the tubercula quadrigemina, and beneath the poste- 
rior border of the corpus callosum. 

Directly behind the third ventricle are found the Tuber- 
cula Quadrigemina, Fig. 13, a, e. They consist of four 
round tubercles or elevations, separated on the surface by 
grooves, but joined at their bases. They occupy a plane in- 
clined obliquely backwards and downwards. The anterior 
and superior are called nates; the posterior and inferior are 
named testes, and are smaller than the nates. They, with the 
posterior commissure, form the roof of the way from the third 
to the fourth ventricle, or the aqueduct of Sylvius. 

Before proceeding further with the dissection, it will be 
necessary to remove the encephalon from the cavity of the 
cranium. It might be taken out before the dissection of the 
cerebrum is commenced. This is not necessary, however, if 
it can be examined when fresh, or if the subject has previously 
been injected with solution of chloride of zinc. To remove 
the encephalon, the subject should be placed on the back, 
with a block under the shoulders, so that the head can be 
depressed sufficiently to allow it to rest on one hand, while 
the vessels, nerves, &c., are divided with the other. 

In raising the anterior lobes, the bulbs of the olfactory 
nerves must be removed with some care from the cribriform 
fossas ; or they may be allowed to remain for the purpose of 
examining them after vN^ards in situ. The op^^c nerves must be 
divided at the sella turcica, just before they enter the optic 
foramina ; also the internal carotids. Immediately behind the 
optic chiasm, which will now be seen, is the infundibulum, 
extending from the tuber cinereum, on the base of the brain, 
to the pituitary gland, which occupies the sella turcica ; this 
may be cut across, if it be desired to examine the gland 
in situ, otherwise the scalpel may be carried around it so 
as to remove the greater part of it in connection with the 
infundibulum. The whole of the pituitary body cannot 
well be dissected out without cutting away the posterior 
clinoid processes. The infundibulum is very easily broken, 
hence some care is necessary to preserve it. The third pair 
of nerves will be seen perforating the dura mater behind, and 
outside of the posterior clinoid processes. The fourth pair 
run along the margin of the tentorium; they are very small, 



THE CEEEBRUM. 67 

and iisuallj lie concealed just beneath its edge. Tlie ffth 
pair are large, and perforate the dura mater a little below 
the margin of the tentorium ; they are readily exposed by 
cutting through the tentorium directly over them.. The 
sixth pair are much smaller, and will be seen a little further 
back and nearer to the median line. The seventh "pair are 
situated more externally, and nearer to the petrous portion 
of the temporal bone. The eighth pair consist of several 
fasciculi, and are a little nearer to the median line and further 
back than the preceding. The ninth pair will be observed 
near the foramen occipitale. These nerves must all be 
divided, as they are brought into view, with a sharp scalpel 
or with the scissors. The tentorium must be cut through on 
each side before all the nerves can be divided. The spinal 
marrow is to be cut across by carrying the scalpel as far 
down as convenient through the occipital foramen, care being- 
taken, at the same time, to sever the vertebral arteries. 
Having divided all these parts, the brain is easily removed 
by carrying one or two fingers down so as to dislodge the 
medulla oblongata and cerebellum, while the whole is steadied 
and carefully supported with the other hand. It is hardly 
necessary to remind the student of the necessity of handling 
the encephalon with great care, in order to preserve it entire. 

If the cerebellum now be pushed a little backwards, and 
away from the testes, the valve of the brain and the processus 
cerehelli ad testes^ Fig. 13, 72, will be seen. To obtain a good 
view of these, the student may divide the cerebellum in the 
median line and down to a level with the valve. Havins; 
examined the valve in situ, he may continue the incision to 
near the base of the cerebellum. Thus, dividing this organ 
need not interfere with its examination at another time". 

The interior of the Fourth Ventricle, Fig. 10, v. Fig. 16, 
will be distinctly seen by separating the tAVO halves of the 
cerebellum. It consists of a lozenge-shaped space, situated 
behind and below the tubercula quadrigemina, which sepa- 
rate it from the third ventricle. Its boundaries arc formed 
by the medulla oblongata, the cerehelluni, and the cerehnim, so 
that it may be regarded as a space occurring incidentally 
between all these parts. The object to be gaiued by studying 
it as a cavity is simply to learn the location of the parts with 
which it is in relation. 

Its floor is formed by the upper and posterior surface of 
the medulla oblongata ; its roof is arched from above down- 



68 DISSECTION OF THE HEAD AKD NECK. 

wards and from before backwards, and may be considered as 
curved laterally with the concavity looking towards the 
ventricle. 

The following parts enter into the formation of its roof: — 
In the ui:)per and anterior part are the valve of the brain 
and the processus cerebelli ad testes. The valve is of a tri- 
angular shape, the apex being joined above by a narrow 
band to the testes, the base to the cerebellum, and the sides 
to the processus cerebelli ad testes. It consists of a thin 
white lamina, covered by a layer of gray substance. Its 
upper surface, especially near the base, presents several trans- 
verse ridges, resembling the lamellated arrangement of the 
cerebellum. The fourth pair of nerves arise from it and the 
processes on its sides. 

The Processus Cerebelli ad Testes are two bands of 
medullary fibres, one extending from the centre of each 
hemisphere of the cerebellum to the testes, and through them 
to the cerebrum. In the lovjer and 'posterior part of the roof 
there are, in the median line, two projections ; the upper one 
is named the nodidus^ the lower one the uvula. These promi- 
nences are situated on the inferior vermiform process on the 
lower part of the median lobe of the cerebellum. On each 
side of the uvula, and u.nited to it, is a small protuberance 
termed the tonsil. Extending from the flocculus or pneumo- 
gastric lobe on the one side, to the nodulus in the centre, and 
thence across to the corresponding lobe of the opposite side, 
may be seen a thin, white, delicate membrane, composed of 
transverse fibres, and named the posterior medullary velum. 
It forms a commissural connection between the parts with 
which it is connected. It presents a free, concave border, 
which looks into the ventricle. 

The following points are observed in the floor of the fourth 
ventricle : A fissure is seen in the median line extending 
from the lower orifice of the aqueduct of Sylvius above, to 
a slight depression in the medulla oblongata called the ven- 
tricle of Arantius. The lower part of this fissure is named 
the calamus scriptorius. The whole length of the fissure is 
about an inch and a half. The corpora restiformia commence 
at the ventricle of Arantius, and diverge as they pass up- 
wards and outwards to enter the cerebellum. In the upper 
part are the crura cerebelli, which are composed of the trans- 
verse medullary fibres of the pons Varolii, and are here seen 



THE CEREBELLUM. 69 

entering the cerebellum. The ^posterior pyramids are two 
bodies, one on each side of the lower part of the fissure. 
The superior surface of the pons Yarolii forms a part of the 
floor just behind and below the tubercula quadrigemina. 
The fasciculi innominati, or corpora teretes, also pass up 
through the posterior part of the medulla oblongata, and in 
the floor of the fourth ventricle. In the lower part of the 
floor are observed white transverse fibres, called linece trans- 
versoe. The PORTio mollis arises in part from some of these 
fibres. A thin layer of gray neurine covers the greater part 
of the walls of this cavity, and the whole is lined by a serous 
membrane, which is continued into the third ventricle through 
the aqueduct of Sylvius, but not into the subarachnoid space 
immediately below. 

The pia mater sends into the fourth ventricle two pro- 
longations called choroid plexuses. Before proceeding farther 
with the dissection, the reflection of the arachnoid from the 
cerebellum to the medulla oblongata should be noticed. 
Quite a space is left beneath it, occupied principally by 
areolar tissue. This is called the posterior subarachnoid space. 
It will be observed that the arachnoid adheres closely to the 
surface of the medulla oblongata, so that fluid cannot readily 
pass from the posterior subarachnoid space in the cranium, 
to the one in the spinal canal. It may be remarked here, 
that the subarachnoid spaces in the cranium communicate 
for the most part freely with each othe!r. 



THE CEREBELLUM. 

The dissection of the cerebellum may now be commenced. 
Some of its parts have already been noticed in connection 
with the fourth ventricle. Its location and relations in the 
cranial cavity were seen at the time the encephalon was 
removed. It differs in form and external appearance very 
materially from the cerebrum. Its transverse diameter is 
greater than the antero-posterior, while its two hemispheres 
are connected above and below by elevations. Instead of con- 
volutions, its exterior surface presents numerous concentric 
lamella} separated by sulci ; these have, for the most part, a 
transverse direction, and are more numerous on the upper 
than on the lower surface. It is composed of white medul- 
lary substance internally, and gray matter externally. The 



70 DISSECTION OF THE HEAD AND NECK. 

gray substance, however, does not cover the bottoms of the 
deep sulci. Its superior and inferior surfaces are separated 
by a well marked border, and a deep horizontal fissure. It 
presents two notches, one before for the tubercula quadri- 
gemina and the crura cerebelli, and one behind for the falx 
cerebelli and inferior occipital ridge. The posterior notch 
terminates below and anteriorly in an excavation which cor- 
responds to the medulla oblongata. 

The two hemispheres are united by a median lohe, the upper 
part of which is termed the siqoerior vermiform process^ and 
the lower part the inferior vermiform process. The upper sur- 
face is sloping from the centre, while the under surface of 
each hemisphere is convex, and separated by a deep depres- 
sion, named the vallecula^ or valley. 

The superior surface, Fig. 14, of each hemisphere presents 
two lobes ; an anterior^ or square lohe^ and a posterior^ or semi- 

Fig. 14. 




A View of the Superior Face of the Cerebellum. — 1,1. The circumference 
of the cerebellum, 2. The space between its hemispheres behind. 3. One of the 
hemispheres of the cerebellum, showing the lamella3 which compose it. 4. The 
superior vermiform process. 5. The tubercula quadrigemina. ^. Section of the 
crura cerebri. 

lunar hbe^ divided by a deep sulcus. The two anterior lobes 
are connected to each other by the transverse laminas of the 
superior vermiform process, which is situated between them. 
The two posterior lobes are separated from each other by 
the posterior notch, but are connected to each other by trans- 
verse bands at the bottom of the notch. These lobes'' consist 
of lobules, which again are composed of laminge. 



THE CEEEBELLUM. 71 

The inferior surface, Fig. 15, of each hemisphere presents 
five lobes separated by sulci. 

The inferior posterior lohe is situated immediately below the 
superior posterior, and separated from its fellow by the pos- 
terior notch. 

The digastric hie is larger, and is seen near the anterior 
and external border of the hemisphere. This lobe is con- 
nected to its fellow on the opposite side by transverse lamellae, 
which extend through the pyramid across the valley. Its 
outer extremity is broad, and divided into two parts. 

The gracilis lobe is situated between the two preceding. It 
has a transverse direction. 

Fig. 15. 




A View op the Inferior Surface op the Cerebellum and a portion op the 
Medulla Oblongata. — 1,1. The circumference of the cerebellum. 2,2. The two 
hemispheres of the cerebellum. 3. Lobus amygdaloides. 4. The inferior ver- 
miform process. 5. Lobus nervi pneumogastrici. 6. The calamus scriptorius. 
7. Its point. 8. Section of the medulla oblongata. 9. Points to the origin of the 
pneumogastric nerve. 

lHhQ flocculus^ or pneumogastric lohe, Fig. 15 (5), is attached 
to the hemisphere by a pedicle. It is situated anteriorly by 
the side of the valley, and just behind the crus cerebelli, 
close to the eighth nerve. Its surface is divided into small 
lamellae. The two flocculi, as before mentioned, are con- 
nected to each other by the posterior medullary velum. 

The amygdaloid, or tonsilUlic lobes, were seen in the dissec- 
tion of the fourth ventricle. These two lobes form the lateral 
boundaries of the valley, and are connected to each otlier by 
the uvula. 

The superior vermiform process extends from the posterior 



72 



DISSECTION OF THE HEAD AND NECK. 



to tlie anterior notch. It is much larger anteriorly where it 
overhangs the valve of the brain, and is in apposition with 
the tubercnla quadrigemina, than it is posteriorly. It is 
crossed by curved lamellae, which are convex anteriorly. 

The inferior vermiform j^rocess has a crucial form. The pos- 
terior limb projects backwards in the posterior notch, the 
anterior extends forwards into the fourth ventricle, while the 
lateral or transverse are connected to the hemispheres. It 
presents in the median line three prominences : the pyramid 
behind, next to this, in front, the uvula, and anterior to this 
the nodulus. The last two form a portion of the roof of the 
fourth ventricle. 

The internal structure of the cerebellum may be seen 
by making two vertical incisions from before backwards, 
commencing at the anterior notch. One of these incisions 
should divide the middle lobe in the median line ; the other 

Fig. 16. 




A View of the Arbor Vit^ and the Fundaiiextal Portion of the Cerebel- 
lum, TOGETHER WITH THE FlOOR OF THE FoURTH VENTRICLE. — 1. The tubercula 

quadrigemina. 2. The superior surface of the cerebellum. 3. Its ioferior surface, 
and also the arbor vit^e. In the trunk of the arbor vitsB are seen three fasciculi 
running up to the tubercula quadrigemina. Themost internal of these is— 4. A fibrous 
layer, in which are collected all the filaments which pass from the parietes of the 
aqueduct of Sylvius to the inferior vermiform process. 5 Is the fasciculus outside 
of the preceding, which runs from the trunk of the arbor vitee behind the tubercula 
quadrigemina. 6 Is that from which all the fasciculi of the superior vermiform 
process pass to the tubercula quadrigemina. 7. A very delicate medullary layer, 
which passes from the anterior surface of the crus cerebelli under the cineritious 
matter of the cerebrum. 8. The anterior extremity of the fourth ventricle, drawn 
back and leading to the aqueduct of Sylvius. 9. Middle furrow on the floor of the 
fourth ventricle. 10. Tracts of nervous matter, running to the auditory nerve. 11. 
Elevated portion of the same on the floor of the fourth ventricle. 12. Middle fis- 
sure on the calamus scriptorius. 13. Corpora Eestiformia. 14. Lateral portion of 
the spinal marrow. 



THE MEDULLA OBLONGATA. 73 

should be carried tliroiigh one of the hemispheres so as to 
leave about one-third of it on the inner side, and two-thirds 
on the outer side. The arrangement of the white or medul- 
lary substance is distinctly seen on the surfaces of these sec- 
tions. It presents, in ^both, a beautiful arborescent appear- 
ance, which has been named the arhor vitce. The one in the 
middle lobe is the middle arhor vitoe^ and the one in the hemi- 
sphere, the lateral arhor vitce. The central mass is the trunk 
of the tree, and from this spring branches, which divide into 
smaller branches, and these again into twigs and leaflets. In 
this way the medullary fibres diverge from the centre to the 
periphery, so as to be placed in connection with a large ex- 
tent of cineritious surface. In the centre of the trunk of 
the lateral arbor vitae is a mass of grayish-yellow matter, 
with indented edges : this is the corpus dentatum^ corpus 
rJiomboideum^ or the ganglion of the cerebellum. It consists 
of a capsule of gray substance, filled with white fibres, inter- 
mixed with gray neurine. The capsule is perforated ante- 
riorly by the fibres of the corpus restiforme. 

The Ceeebellum is about one- eighth the size of the cere- 
brum. Its white central mass is connected with the cere- 
brum, through the processus cerebelli ad testes^ and with the 
medulla oblongata, through the corpora restiformia and the 
arciform fihres which come from the corpora pyramidalia; 
the two hemispheres are connected by the transverse fihres of 
the pons Varolii. These commissural fasciculi should be 
carefully observed by the student, as it is through them en- 
tirely that the cerebellum is placed in relation with the other 
parts of the nervous system. 

The Medulla Oblongata, Fig. 17 (i 3), may next be exa- 
mined. This consists of an intermediate section betAveen the 
spinal marrow and the cerebrum and cerebellum ; it is a sort 
of unfolding of the spinal marrow preparatory to the con- 
tinuation of its fibres upwards into the two bodies just men- 
tioned. Although it is convenient to speak of it as a distinct 
part, the student should bear in mind that it is merely a 
portion of one continuous structure. It gives origin, it is 
true, to nerves which have specific functions, but tliis does 
not, in an anatomical point of view, isolate it at all from 
other parts with which it is structurally connected. 

It commences just below the foramen occipitale, and extends 
7 



74 DISSECTION OF THE HEAD AND NECK. 

upwards to tlie pons Yarolii. Its direction corresponds to the 
inner surface of the cuneiform process of the occipital bone 
and the commencement of the spinal canal. Anteriorly and 
laterally, it is simply covered by pia mater and arachnoid 
membrane ; posteriorly, it is, as has already been seen, in 
relation with the cerebellum and fourth ventricle. 

Each lateral half presents four elevations or bodies, named 
corpus pyramidale^ corpus olivare^ corpus restiforme^ and coipus 
pyramidale posterius. The two anterior pyramidal bodies 
are separated by a fissure, which is a continuation of the 
anterior fissure of the spinal marrow. At the bottom of this 
fissure are observed transverse commissural fibres; and, 
about an inch below the upper extremity, are seen several 
fasciculi, which decussate, connecting each half of the spinal 
marrow Avith the opposite hemisphere of the brain. The 
two posterior pyramidal bodies are also separated by a fissure, 
which is a continuation of the posterior fissure of the spinal 
marrow. A part of this fissure is the calamus scriptorius. 

The CoEPORA Pyramid ALIA, Fig. 17(2 o), are a continuation 
of the anterior columns of the spinal marrow upwards. They 
increase in size iip to the pons Varolii, where they become 
suddenly constricted, and immediately enter that body. They 
diverge slightly as they ascend. At the upper end of the fis- 
sure, and between their upper extremities, is a small depres- 
sion, called the foramen coccum. Each body is composed of 
fibres coming from the anterior column of the spinal marrow 
of its own side, and also of fibres from that of ^ the opposite 
side. These fibres continue upwards, through the pons Ya- 
rolii and crura cerebri, to the cerebral hemispheres. 

The Corpora 0LiYARiA,Eig.l7 (22), are situated behind, and 
external to the anterior pyramids. They do not extend quite 
up to the pons ; nor are they quite as long as the pyramids. 
The upper extremities are more prominent than the lower. 
Externally, they consist of white fibrous tissue; internally, each 
contains a mass of gray substance called the oUvary ganglion, 
or corpus dentatum of the olivary body. The structure and 
appearance of this is similar to the corpus dentatum of the 
cerebellum. On the inner side, its capsule is open, and the 
gray matter which it contains is continuous with that of the 
centre of the medulla oblongata; it is also continuous with 
the gray substance of the pons. The fibres of the olivary 
bodies are continued upwards into the upper and posterior 



BASE OF THE BRAIN. 75 

part of tlie crura cerebri, and thence to the optic thalami and 
tnbercula quadrigemina. The two olivary bodies are joined 
to each other behind the anterior pyramids, and form a part 
of the floor of the fourth ventricle. 

The Corpora Eestiformia, Fig. 17 (21), are observed be- 
hind the olivary bodies. They are separated from each other, 
below, by the posterior median fissure, and, above, by the 
fourth ventricle. They are a continuation of the posterior 
lateral columns of the spinal cord upwards to the ganglia of 
the cerebellum. 

The Corpora Pyramidalia Posteriora, or Innominata, 
are seen in the floor of the fourth ventricle, one on each side 
of the median fissure. Their fibres extend upwards to the 
cerebrum. 

The Arciform Fibres arise from the anterior pyramids, and, 
curving round the olivary bodies, join the corpora restiformia. 
They are very irregular. Sometimes they are seen above and 
below the olivary bodies, and again they spread out over them. 

The grooves, between which the olivary body on each side 
is situated, are occupied by the roots of nerves. 

The BASE of the brain may now be examined. There are 
three subarachnoid' spsLces, to be noticed, in the first place, on 
the base of the brain. The two lateral are formed by the 
arachnoid passing from the lower surfaces of the middle 
to the anterior lobes, without dipping into the fissures of 
Sylvius. The anterior is situated in front of the pons Varolii, 
and between the middle lobes. These spaces are filled with 
loose areolar tissue, and are capable of containing a consider- 
able quantity of serum. The arachnoid, where it is reflected 
to form these spaces, is quite thick and strong. 

The under surface of the brain, it will be observed, presents 
an appearance very different from the upper. Taking the 
encephalon, the following prominent points will be noticed: 
On the sides, are the anterior and middle lobes of the 
cerebrum, separated by the fissures of Sylvius ; behind 
the middle lobes, and separated from them by the trans- 
verse fissure, are the hemispheres of the cerebellum. Thus, 
the encephalon presents six prominent parts^ situated later- 
ally on its inferior surfixce. In the space between these 
parts, and occupying tlie centre, are the following, commenc- 
ing posteriorly: The medulla oblongata, situated between 



76 



DISSECTION OF THE HEAD AND NECK. 



the hemispTieres of the cerebellum ; directly in front of this, 
the pons Varolii ; anterior to it, the crura cerebri, and, be- 



Fig, 17. 




A View of the Base of the Cerebrum and Cerebellum, together with their 
Nerves. — 1. Anterior extremity of the fissure which separates the hemispheres of 
the brain. 2. Posterior extremity of the same fissure. 3. Anterior lobe of the 
cerebrum. 4. Its middle lobe. 5. Fissure of Sylvius. 6. Posterior lobe of the 
cerebrum. 7. A part of the infundibulum. 8. Tuber cinereum. 9. Corpora albi- 
cantia. 10. Pons Tarini. 11. Crura cerebri. 12. Pons Varolii. 13. The top of the 
medulla oblongata. 14. Posterior prolongation of the pons Varolii. 15. Middle of 
the cerebellum. 16. Anterior part of the cerebellum. 17. Its posterior part, and 
the fissure of its hemispheres. 18. Superior part of the medulla spinalis. 19. Mid- 
dle fissure of the medulla oblongata. 20. Corpus pyramidale. 21. Corpus resti- 
forme. 22. Corpus olivare. 23. Olfactory nerve. 24. Its bulb. 25. Its external 
root. 26. Its middle root. 27. Its internal root. 28. Optic nerve beyond the 
chiasm. 29. Optic nerve behind the chiasm. 30. Motor oculi, or third pair of nerves. 
31. Fourth pair, or pathetic nerves. 32. Fifth pair, or trigeminus nerves. 33. Sixth 
pair, or motor externus. 34. Facial nerve. 35. Auditory nerve. 36,37, 38. Eighth 
pair of nerves. (The ninth pair are not seen.) 



tween them, the locus perforatus medius and the eminentise 
mammillares ; in front of the eminentige, the tuber cinereum, 



BASE OF THE BRAIN. 77 

which is placed between the optic tracts, and behind the optic 
chiasm; in front of the chiasm is the fissure which separates 
the anterior lobes ; on the outside of each optic tract is the 
commencement of the fissure of Sylvius, with the locus per- 
foratus lateralis and the peduncle of the corpus callosum. The 
relative position of these different parts on the base of the 
encephalon, should be carefully noted by the student. 

The Pons Yaholii, Fig. 17 (12), contains the fibres which 
constitute the great commissure between the hemispheres of 
the cerebellum, and also the fibres which are prolonged from, 
the medulla oblongata upwards into the crura cerebri. Be- 
sides these two sets of fibres, more or less gray substance is 
found in it, in which other fibres are said to originate. 

It has directly above it the upper portion of the fourth 
ventricle, the tnbercula quadrigemina, and the aqueduct of 
Sylvius. Its lower surface is free, and corresponds to the 
■upper part of the basilar process of the occipital bone. Below 
and behind it is the medulla oblongata. In front of it are the 
crura cerebri. Laterally it terminates in the middle pedun- 
cles of the cerebellum. 

When the pons is cut into, the transverse fibres are found 
to be intersected by longitudinal fasciculi, which are easily 
traced from the corpora pyramidalia upwards to the crura 
cerebri. The transverse fibres which are placed above the 
longitudinal fasciculi have gray substance intermixed with 
them. This gray substance is also intermixed with the fibres, 
which are prolonged upwards from the corpora olivaria. 
Above the gray substance are the fibres which proceed from 
the corpora innominata to the upper part of the crura cerebri. 

The Crura Cerebri, or the Peduncles of the Cerebrum, 
Fig. 17 (1 1), are two large white bodies placed in front of the 
pons Varolii. They are to be regarded as a continuation of the 
spinal marrow upwards to the base of the cerebrum. They 
consist of white fibres which have ascended through the pons 
from the medulla oblongata and those wliicli have originated 
in the pons, together with a mass of gray matter in each crus 
named the locus niger. The inferior fibres are a continuation 
of those which compose the corpora pyramidalia ; the superior 
fibres are a continuation of those of the corpora olivaria and 
innominata. The gray matter is situated between these two 
sets of fibres, and in the central part of each crus. The gray 



78 DISSECTION OF THE HEAD AXD XECK. 

matter of the two crura is connected by the pons Tarini. It 
is continuous below \nt\i the gray neurine of the pons, me- 
dulla oblongata, and spinal marrow, and above, with that of 
the corpora striata and optic thalami. 

If the fibres of the crura be traced upwards into the 
cerebral hemispheres, they will be found to enter the gray 
matter of the corpora striata and optic thalami ; the inferior 
fibres, or those from the corpora pyramidalia, pass into the 
striated bodies, and the superior fibres, or those from the 
corpora olivaria and innominata, into the optic beds. This is 
true, however, only to a certain extent. The termination of 
these fibres in the optic thalami and striated bodies varies ; 
some seem to form a plexiform arrangement in them. The 
corpora striata and optic thalami are the great central 
ganglia of the cerebral hemispheres ; their gray matter forms 
really but a single mass in each hemisphere, and the masses 
of the two hemispheres are joined together by the commis- 
sura mollis of the third ventricle; in the same manner the 
loci nigri, in the crura cerebri, are connected by the pons 
Tarini; the lateral gray masses of the pons Varolii are joined 
together, and the medulla oblongata and the spinal marrow 
are also united in the median line by gray substance. 

Thus the student will see that the white fibres, as well as 
the gray neurine of the spinal cord, are continued through 
the medulla oblongata, pons Varolii, and crura cerebri, up 
into the corpora striata and optic thalami; that although 
the fibres may change their relative position, and the gray 
neurine appear in difterent forms, yet they present an un- 
broken continuity. 

The Locus Peefoeatus Medius, or Poxs Taeixi, Pig. 17 
(i o), is of a gray color. It is placed between the base of the 
brain and the posterior part of the third ventricle, and is per- 
forated by numerous small arteries. It is very thin, and 
easily broken through. It was called 'pons' by tarinus, be- 
cause it extended across from one crus cerebri'^to the other. 

The CoEPORA MAZyDHLLAEiA, or CoEPOEA Albicaxtia, Pig. 
17 (9), are two small round bodies, white externally and gTay 
internally. The white matter is the termination of the anterior 
cornua of the fornix on the base of the brain; the fibres of the 
fornix do not, however, end in these bodies, but are reflected 
upwards and backwards to the upper part of the thalami. 



BASE OF THE BKAIN. 79 

The Tuber Cineeeum, Fig. 17 (s), is a tliin mass of gray 
matter behind the optic chiasm and in the floor of the third 
ventricle. From the centre of this projects downwards the 
infundihulum. This is of a reddish gray color, of a conical 
shape, terminating below in the pituitary gland, and opening 
above into the anterior part of the third ventricle. Its npper 
extremity only is hollow, at least, as a general thing, in the 
adult .brain. 

^'^he Pituitary Gland occupies the sella turcica. It is a 
small body, consisting of an anterior and a posterior lobe. 
The anterior lobe is kidney- shaped, and composed of a yel- 
lowish substance ; the posterior lobe is partly received into 
the anterior. This body is hollow in the foetus, and com- 
municates with the third ventricle through the infundih- 
ulum. It is covered by a layer of the dura mater. To 
dissect it in situ^ the posterior clinoid processes should be 
broken away. 

When the optic chiasm is raised, a thin layer of gray 
substance is seen, called the lamina cinerea. This extends 
from the tuber cinereum behind to the corpus callosum in 
front. Laterally, it joins on each side the perforated place 
at the inner extremity of the fissure of Sylvius. Its upper 
surface looks into the anterior part of the third ventricle. 
The chiasm of the optic nerves is connected by gray matter 
to the lamina cinerea. 

On the sides of the lamina cinerea, and crossing the 
lateral perforated places, are seen two white fibrous bands, 
which pass forwards to terminate in the anterior border of 
the corpus callosum. These are named the peduncles of the 
corpus callosum. 

The Loci Perforati Laterales are situated, one at the 
commencement of each fissure of Sylvius. They are per- 
forated by numerous small arteries which are intended, 
mostly, for the supply of the corpora striata. 

The Fissure of Sylvius, Fig. 17 (5), separates the anterior 
and middle lobes. It serves to increase greatly the exterior 
surface of the brain and the number of convolutions. As it 
passes outwards, it divides into two branches, which sur- 
round several small convolutions. These constitute the 
island of Reil. They correspond to the outer part of the 
corpus striatum. 



80 DISSECTION OF THE HEAD AND NECK. 

The Lobes of tlie cerebrum, Fig. 17 (3, 4, e), are six in num- 
ber, three for each hemisphere. These are not seen on the upper 
part of the brain, and even on the base there is no natural line 
of separation between the posterior and middle. The middle 
is the most prominent ; it occupies the middle fossa in the 
base of the cranium. The posterior rests on the tentorium, 
which separates it from the cerebellum, and at the same 
time supports it. The anterior lobe lies on the orbital por- 
tion of the frontal bone. It is separated from the corres- 
ponding lobe on the opposite side by the great longitudinal 
fissure. The two posterior lobes are separated from each 
other by the same fissure. The extent of this fissure is 
worthy of notice. N^o one can have any correct idea of the 
number of convolutions or the extent of exterior surface 
which each hemisphere of the cerebrum presents, without a 
knowledge of this fissure. 

The Gkeat Transverse Fissure separates the posterior 
lobes from the cerebellum. It opens into the central exca- 
vation in front of the pons Varolii, passing round on each 
side of that body, and under the crura cerebri. This fissure 
leads into the middle cornu of each lateral ventricle, and also 
into the third ventricle, beneath the posterior border of the 
corpus callosum. It is in this part of the transverse fissure 
that Bichat described a communication between the cavity of 
the lining membrane of the third ventricle and the cavity of 
the arachnoid, external to the brain. It is called the Canal 
of Bichat. This anatomist described this communication as 
being of a tu.bular form, and surrounding the venaB Galeni. 
There can be no doubt that it does exist in some cases. 



ORIGIN OF the cerebral NERVES, 

The cerebral nerves consist of nine pairs. With the excep- 
tion of the spinal accessory, a part of the eighth pair, they 
all arise from some part of the encephalon; they escape from 
the cranial cavity through different foramina. There is no 
difference between the corresponding nerves of the two sides. 
Although each pair has a particular name, they are gener- 
ally designated by numbers — as first, second, third, &c. 

The First Pair, or Olfactory Nerves, Fig. 17 (23), have 



ORIGIN OF THE CEREBRAL NERVES. 81 

eacli three roots — one arising from the fissure of Sylvins, an- 
other from the corpus striatum, and the third from the poste- 
rior convolutions of the anterior lobe. The last one is situated 
between the others, and consists of gray matter. The trunk 
formed by the union of these three roots runs forward about 
two inches on the under surface of the anterior lobe, and then 
swells into a bulb, which rests on the cribriform plate of the 
ethmoid bone. The olfactory nerves are of a prismatic form, 
each being lodged in a groove on the under surface of the 
anterior lobe, to which it is bound by the arachnoid membrane 
passing over it, but not around it. They are composed of 
white and gray substance, and are softer than the other nerves. 
The bulbs are called the olfactory lobes, and might very prop- 
erly be considered the true origin of the olfactory nerves. 
The filaments arise from the bulbs in two series on each side, 
and pass through the cribriform plate of the ethmoid, the 
outer series to the external wall, and the inner to the internal 
wall of the nasal fossa. 

The Second Pair, or Optic, Fig. 17 (2 s), arise from the tuber- 
cula quadrigemina, corpora geniculata, and optic thalami. The 
part between the origin of each nerve and the chiasm is called 
the oj)tic tract. This is soft and flattened, and rests on the 
crus cerebri, to which it adheres slightly. The part anterior to 
the chiasm is round, and invested by neurilemma. The optic 
tracts converge towards the chiasm, while the optic nerves 
diverge as they proceed towards the orbits. The chiasm is 
formed by a decussation of the inner fibres of each nerve, 
while the outer fibres continue on without crossing. The 
chiasm is connected to the tuber cinereum by a few fibres. 
Transverse fibres have been described in this commissure. 
As the optic nerves pass through the optic foramina, the neu- 
rilemma is continuous with the periosteum lining the orbits ; 
also with the sclerotic coat, as each nerve enters the ball of 
the eye. 

The Third Pair, or Oculo Motor, Pig. 17 (3 0), arise from 
the crura cerebri, near the pons Tarini. They can be traced 
into the substance of the crura, to the gray matter, or loci nigri. 
Each nerve consists of a round white cord, passes through 
the wall of the outer part of the cavernous sinus, and en- 
ters the orbit through the foramen splicnoidalc, to be distri- 
buted to the superior, internal, and inferior recti muscles; 



82 DISSECTION OF THE HEAD AND NECK. 

also to the inferior oblique and the levator of tlie upper 
eyelid. 

Tlie FouKTH Paie, or Pathetic, Fig. 17 (3 1), arise from the 
valve of Yieussens and processus cerebelli ad testes. They 
are very small, and thread-like. Each passes through the 
walls of the cavernous sinus, and sphenoidal foramen to go to 
the superior oblique muscle of the eyeball. These nerves are 
so small and delicate, that the student must be very careful 
in tracing them, or he will either break or lo3e sight of them. 

The Fifth Paie, Trifacial, or Trigeminal, Fig. 17(32), 
have each two roots, arising apparently from the pons Varolii. 
The small root consists of motor filaments, and is situated 
above the large or sensor. The sensor portion of this nerve 
can be traced to near the floor of the fourth ventricle, or to the 
corpus innominatum; the motor portion is connected in its 
origin with the fibres of the corpus pyramidale, with which it 
is associated in f auction. The two roots, after leaving the pons, 
unite to form a large cord or fasciculus, which passes beneath 
the tentorium, perforates the dura mater, and rests on the 
petrous bone, in its course to the middle fossa of the base 
of the cranium, where the sensor portion expands into the 
Gasserian ganglion. This ganglion is of a triangular shape, 
and, when fully exposed, presents a plexiform arrangement, 
with gray neurine intermixed. It is covered by a lamina of 
the dura mater, which adheres closely to it. The motor fila- 
ments pass over its under surface, and not through it. From 
its base proceed the ophthalmic and the superior and inferior 
maxillary branches. The first of these passes through the 
sphenoidal foramen; the second^ through the foramen ro- 
tundurn ; and the third^ through the foramen ovale. All the 
motor filaments accompany the inferior m.axillary branch. 
The dura mater obtains filaments from the fifth pair. It 
will be observed that this nerve resembles the spinal nerves 
in having a motor and a sensor root, and the sensor portion 
having a ganglion on it. 

The Sixth Pair, or Abducentes, Fig. 17 (33), arise from 
the corpora pyramidalia, just as they enter the pons. Each 
nerve passes through the wall of the cavernous sinus and the 
sphenoidal foramen to reach the external rectus of the eye- 
ball. While passing through the wall of the cavernous 



OKIGIN OF THE CEKEBRAL NERVES. 83 

sinus, it is joined by one or two filaments from the sympa- 
thetic. They are much smaller than the third pair, but larger 
than the fourth 

The Seventh Pair, Fig. 17 (34), consist each of two 
nerves, the portio dura, or facial, and the portio mollis, or 
auditory nerve. The jportio mollis is the largest of the two, 
and is situated behind the portio dura. It arises in the floor 
of the fourth ventricle by the linese transversse, and from gray 
neurine in the corpus olivare, passes round the restiform 
body to join the portio dura just below the crus cerebelli. 

The por^zb dura arises from the corpus innominatum, near the 
calamus scriptorius, and passes through the corpus restiforme; 
it is joined by the auditory nerve, as before mentioned, and 
both pass outwards to the meatus auditorius internus. The 
portio mollis goes to the labyrinth of the ear, the portio dura 
to the muscles of the face, &c. 

The Eighth Pair, Fig. 17 (se), consist each of the glosso- 
pharyngeal, the pneumogastric, and the spinal accessory of 
Willis. The glosso-pharyngeal and pneumogastric arise on 
each side, by quite a number of filaments, in the groove be- 
tween the olivary and restiform bodies. The former is 
situated a little above the latter, and is much smaller. Their 
roots can be traced to gray matter — respiratory ganglion — in 
the posterior part of the medulla oblongata, and near to the 
floor of the fourth ventricle, upon which there are three or 
four small protuberances corresponding to the origin of these 
nerves. The spinal accessory arises from the side of the 
spinal marrow, between the roots of the cervical nerves, 
commencing as low down as the fifth or sixth cervical verte- 
bra. The round cord or nerve which is formed by these 
roots passes upwards behind the ligamentum denticulatum 
to the cavity of the cranium, entering it through the foramen 
occipitale, to join the two preceding nerves. It is very fre- 
quently connected by filaments to the first and second cervi- 
cal nerves. 

The eighth nerve leaves the cranial cavity through the 
jugular foramen, being separated from the internal jugnlar 
vein by a ligamentous band. 

The Ninth Pair, or Hypoglossal, arise by several fila- 
ments in the groove between the olivary and pyramidal bodies. 
Each nerve corresponds in origin to the anterior roots of the 



84 DISSECTION OF THE HEAD AND NECK. 

spinal nerves. It passes throngh tlie anterior condyloid 
foramen, and in its cranial course usually consists of two or 
more fasciculi. 

The study of tlie cerebral nerves is rendered perhaps more 
complicated to the student on account of each nerve being 
designated by a particular name. Their origin is necessarily 
more difficult to learn than that of the spinal nerves ; this 
results from the gray neurine with which they are connected 
being more scattered about and not so easily located. If we 
were able to see clearly and distinctly all the gray matter 
with which the different cerebral nerves are connected in 
their origin, we should probably observe the same simplicity 
in its arrangement as in that of the spinal marrow. 

The student should endeavor to acquire familiarity with 
these nerves by studying them according to their functions, 
and in connection with the parts to which they are distri- 
buted. If, for instance, he refers to the nervous endowment 
of the tongue, he will at once see the necessity of this organ 
being supplied with at least three different kinds of nerves. 
It contains muscles which must be supplied with a motor 
nerve; and if these muscles can act independently of the 
will, as well as under its direction, then they must be sup- 
plied with both voluntary and involuntary motor filaments. 
Like nearly all other parts of the body, it must have a nerve 
of general sensibility, and, as it is the seat of taste, it must 
have a nerve of special sensihility. He should learn to con- 
template other organs and other parts of the body, in regard 
to their nervous endowment, in the same manner. 

The third, fourth, sixth, and ninth nerves may be regarded 
as being associated with the motor portion of the fifth nerve, as 
the distribution of all these motor nerves corresponds to that 
of the sensor portion of the fifth. As the fifth is the nerve of 
general sensibility to aU parts of the face, superficial as well 
as deep seated, so would it then also be the nerve of volun- 
tary motion to all the muscles of the same parts. This would 
leave only the four nerves of special sensibility and the por- 
tio dura, an involuntary motor nerve, to be distributed to the 
head ; the pneumogastric and spinal accessory going to sup- 
ply other parts. The following table will exhibit to the 
student, at a glance, the functional divisions of the cerebral 
nerves : — 



AETEBIES OF THE BKAIJS". 85 

pist. Olfactory. 

o Q 1 2d. Optic. 

Special Sensation . . . -^ r-., i j-^ 

I ith. Auditory. 

[8tli. Gustatory. 

r> cs r 5th. Triffeminal. 

Common Sensation . . . < q, , t, . • 

I 8th. Pneumogastric. 

f 3d. Oculo-motor. 
1 4th. Pathetic. 
Voluntary Motion . . . ^ 5th. Trigeminal. 
( 6th. Abducens. 
[9th. Hypoglossal. 



Involuntary Motion 



7th. Facial. 

8th. Spinal accessory. 



AETEKIES OF THE BRAIN". 

The arteries of tlie brain are derived from the internal 
carotid and the vertebral. Each internal carotid gives off at 
the base of the brain the anterior and middle cerebral, and 
the posterior communicating branch. 

The Anterior Cerebral Artery, Fig. 18 (i 3), is directed 
forwards and inwards to the fissure in front of the chiasm of 
the optic nerves. Just before it enters the fissure which separ- 
ates the anterior lobes of the cerebrum, it is connected to the 
anterior cerebral artery of the opposite side by a transverse 
anastomosing branch named the Anterior Communicating Ar- 
tery^ Fig, 18 (1 4). This artery is usually not more than one 
or two lines in length. It completes the circle of Willis 
anteriorly. The anterior cerebral arteries then enter the 
fissure together, and pass upwards over the anterior extremity 
of the corpus callosum, and backwards on its superior sur- 
face to its posterior extremity. They are sometimes called the 
arteries of the corpus callosum^ where they rest on that body. 

The Middle Cerebral Artery, Fig. 18 (12), passes out- 
wards and backwards to the fissure of Sylvius, in which it 
gives off a great number of branches. To trace this artery 
in its course, the anterior lobe must be separated from tlie 
middle, so as to expose the whole of the fissure of Sylvius. 

The Posterior Communicating Artery, Fig. 18 (y), passes 
8 



86 



DISSECTION OF THE HEAD AND NECK. 



backwards to join the posterior cerebral artery, wbicli is a 
branch of the vertebral. It varies greatly in size. 

The Yektebkal Artekies, Fig. 18 (i), enter the cavity of 
the cranium through the foramen occipitale, and coalesce just 

Fig. 18. 




1. The vertebra] arteries. 2. The two anterior spinal branches. 3. One of tbe 
posterior spinal arteries. 4. The posterior meningeal artery. 5. The inferior cere- 
bellar. 6. The basilar artery. 7. The superior cerebellar. 8. The posterior cere- 
bral. 9. The posterior 'communicating. 10. The internal carotid. 11. The oph- 
thalmic. 12. The middle cerebral. 13. The anterior cerebral. 14. The anterior 
communicating. 

behind the pons Varolii to form the Basilar Artery, Fig. 
18 (e). This artery extends to the anterior border of the 
pons, where it divides into the posterior cerebral arteries. 
The cerebellar arteries are given off', the inferior from the 
vertebral, and the superior from the basilar. 

The Posterior Cerebral Artery, Fig. 18 (s), on each side 
is directed outwards and backwards round the crus cerebri 



ARTERIES OF THE BRAIN. 87 

to tlie great transverse fissure, and to the under surface of 
the posterior lobe of the brain. A short distance from its 
origin it is joined by the posterior communicating branch of 
the internal carotid. 

The Superior Cerebellar Artery, Fig. 18 (7), winds 
round the crus cerebri to the superior surface of the cerebel- 
lum.. It is separated from the preceding artery by the third 
nerve, and accompanies for some distance the fourth nerve. 
It sends a small branch into the meatus auditorius internus. 

The Inferior Cerebellar Artery, Fig. 18 (5), arises 
from the vertebral, and passes round the medulla oblongata 
to the under surface of the cerebellum. It passes between 
the roots of the ninth nerve and in front of the glosso- 
pharyngeal and pneumogastric. 

It will be observed that a free anastomosis exists between 
the arteries at the base of the brain. The internal carotids 
are connected together by the anterior communicating artery, 
while they are both connected to the basilar by the two pos- 
terior communicating arteries. It is by means of these 
communicating arteries that the circle of Willis is formed. 
It will also be noticed that no arterial branch of any con- 
siderable size penetrates the substance of the brain. 

The following parts are to be examined in the base of the 
cranium after the brain has been removed. 

The Dura Mater. — This membrane will be found to 
adhere very closely to the greater part of the base of the 
cranium. It sends out prolongations through the various 
apertures to be continuous with the periosteum, and to 
form sheaths for the nerves. It is firmly attached to the 
margin of the foramen occipitale, but does not adhere to the 
walls of the spinal canal. Its internal surface is everywhere 
lined by the arachnoid. The falx cerebri was examined be- 
fore the removal of the brain, and the tentorium was neces- 
sarily cut in that operation. The student can, however, 
replace it, and retain it in situ with a few stitches, so as to 
get a very good view of it and its connections. 

The Tentorium, Fig.9 (s), forms a horizontal septum between 
the spaces occupied by the cerebellum and posterior lobes of 
the cerebrum. Its convex border corresponds to the transverse 
ridge on the inner surface of the occipital bone, extending 



88 DISSECTION OF THE HEAD AND NECK. 

forwards to the base of the petrons portion of the temporal 
bone. Anteriorly it is attached to the petrous bone, and to 
the clinoid processes of the sphenoid. Its centre is some- 
what raised, so as to form an arch, and has attached to its 
upper surface in the median line the posterior extremity 
of the falx cerebri. Its attachments are such that it is kept 
in a state of tension, and is consequently well adapted to 
support the posterior lobes of the cerebrum and to protect 
the cerebellum. A large oval opening exists in it anteriorly, 
which establishes a communication between the compartment 
of the cerebrum and that of the cerebellum and the spinal 
canal. 

The Falx Ceeebelli is a process of the dura mater, 
which projects into the fissure between the hemispheres of 
the cerebellum. Its upper and broadest extremity is at- 
tached to the under surface of the tentorium ; its lower ex- 
tremity divides into two slips to embrace the foramen occipi- 
tale. Its posterior border is attached to the lower part of the 
vertical ridge of the occipital bone. 

The Sinuses, Fig. 8 and Fig. 19, of the du.ra mater are canals 
for the transmission of venous blood. They are veins which 
derive the fibrous layer of their coats from the dura mater ; 
in form they differ from veins in other parts of the body, but 
not in structure. They have no true valves. Some of the 
small ones vary in number, but there are usually fourteen or 
fifteen altogether. Some of these are single and found in the 
median line, and some exist in pairs. 

The su2oerior longitudinal sinus has already been described; 
also the inferior longitudinal sinus. 

The STRAIGHT SINUS is situated between the laminse of the 
dura mater at the junction of the falx cerebri and tentorium. 
It is formed principally by the venae Galeni and inferior 
longitudinal sinus, and terminates in the torcular Herophili, 
sometimes by two orifices. 

The OCCIPITAL SINUS is in the attached border of the falx 
cerebelli. Sometimes there are two of them. It collects the 
blood from the contiguous parts, and conveys it into the 
torcular. 

The LATERAL SINUSES Commence at the torcular Herophili 
and extend to the jugular foramina, occupying a groove on 
each side in the occipital, parietal, and temporal bones. The 



SINUSES OF THE DURA MATER. 



89 



right one is usually larger tlian the left. They are situated, in 
the horizontal part of their course, along the convex or attach- 
ed border of the tentorium. They are the largest of all the 
sinuses in the dura mater, as they receive the blood from all 
the rest, to empty it into the internal jugular veins. They 
increase in size as they proceed towards the jugular foramina, 
to receive the contents of the petrosal sinuses, the mastoid, 
and also the inferior cerebral and cerebellar veins. The 
inferior or curved portion of each is deeply imbedded in the 
bone, and when cut across presents an oval figure, while the 
horizontal portion projects between two layers of the ten- 
torium, and is of a triangular shape. 

The CAVERNOUS SINUSES are situated one on each side of the 
sella turcica. They are of an irregular shape, and have a reti- 
culated structure internally. Each receives the ophthalmic 
vein of the corresponding side. 



The third and fourth nerves, 
and the ophthalmic branch 
of the fifth, pass through its 
outer wall; the internal ca- 
rotid artery, and the sixth 
nerve, pass between its fibrous 
covering and the serous mem- 
brane which lines it. The 
two cavernous sinuses are 
connected by the circular 
sinus. The petrosal sinuses 
establish a communication be- 
tween them and the lateral 
sinuses. 

The CIRCULAR SINUS sur- 
rounds the pituitary gland, 
from which it receives several 
small veins. 



Fig. 19. 




a. The circular sinus, h. The cavern- 
ous sinus, c. The ophtliahnic vein. d. 
The superior petrosal sinus, c. The in- 
ferior petrosal sinus. /. The transverse 
sinus. (J. The occipital sinus, h. The 
lateral sinus on the right side. i. The 
torcular Herophili. 



The TRANSVERSE SINUS lies 
across the cuneiform process 
of the occipital bone. Some- 
times there arc two of them. 

The SUPERIOR PETROSAL SINUS occupies a groove on the 
upper part of the petrous portion of the temporal bono. 

The INFERIOR PETROSAL SINUS of cach sidc is lodged in a 

8* 



90 DISSECTION OF THE HEAD AND NECK. 

groove along tlie suture, between the petrous and occipital 
bones. 

It will be observed that tbe sinuses at tbe base of the cra- 
nium communicate freely with each other, so as to form a 
sort of venous network. 



AETEEIES OF THE DURA MATEE. 

The arteries of the dura mater are derived from several 
sources. 

The j^NTEEiOE Meningeal are branches of the ethmoidal, 
and enter the cavity of the cranium through the ethmoidal 
foramina. 

The Middle Meningeal is the largest of all the arteries . 
of the dura mater. It passes through the foramen spinosum 
of the great wing of the sphenoid bone. Its terminal branches 
were seen when the calvaria was removed. It ramifies 
between the bone and the dura mater, presenting an, arbores- 
cent appearance. The grooves or furrows in the bone, which 
are occupied by the branches of this artery, vary very much 
in depth. In trephining, the relations of the middle menin- 
geal artery to the osseous walls of the cranium are important 
to be recollected. The situation of the principal trunk is 
indicated externally by a line extending from near the centre 
of the zygoma directly upwards. 

The PosTEEiOE Meningeal Aeteey is a branch of the 
vertebral. It arises nearly opposite the foramen magnum. 

Besides these, the dura mater gets a branch from the inter- 
nal maxillary, through the foramen ovale, which is sometimes 
called the meningea parva; another branch from the ascend- 
ing pharyngeal, through the foramen lacerum medius ; one 
from the internal carotid ; and a fourth from the occipital, 
through the foramen lacerum posterius. 

The nerves of the dura mater are derived principally from 
the fifth pair. 



APPENDAGES OF THE EYE WITHIN THE OEBIT. 91 



Sect. YI. — Dissection of the Appendages of the Eye 

WITHIN THE OkBIT. 

To dissect tlie appendages of the eye within the orbit, the 
orbital plate of the frontal bone mnst first be cut away. This 
can easily be done, after the calvaria has been removed, 
with a small sharp chisel or saw. The former is preferable, 
because it can be accommodated to the inequalities of the 
surface which is to be cut. The lesser wing of the sphenoid 
may also be removed with the orbital plate, care being taken 
not to destroy the optic foramen, nor disturb the contents of 
the sphenoidal fissure. Before removing the orbital ridge, 
the tendinous loop for the passage of the tendon of the 
superior oblique muscle should be examined, or the inner 
extremity of the ridge to which the loop is attached may be 
left. In removing the orbital plate, the periosteum which 
covers its under surface, and to which it is loosely connected, 
should be preserved. 

Before proceeding to examine the contents of the orbit, 
the student will do well to obtain some idea of what they 
consist, and in what part of the orbit each is to be found. 
The dissection must also be conducted slowly and cautiously, 
so as not to destroy any of the minuter structures involved. 
The upper plane of the orbit is occupied on the nasal side 
by the superior oblique muscle, with the pathetic nerve 
resting on it ; in the central portion by the frontal nerve, and 
immediately below it, the levator palpebrae superioris ; and 
in the outer part by the lachrymal nerve, and beneath it the 
upper margin of the external rectus, on the outer side of which 
lies the lachrymal gland. 

The Fkontal Nerve, Fig. 20, enters the orbit above the 
muscles, and proceeds along its central portion, close to the 
periosteum, towards the supra-orbital foramen, where it di- 
vides into the supra- orbital and frontal branches. The former 
sends filaments to the upper eyelid, and then passes through 
the supra-orbital foramen to the forehead; the latter giv^es off 
filaments to the eyelid, also one to the frontal sinus, and one 
which anastomoses with the external nasal; its terminal 
branches are distributed on the forehead. 



92 



DISSECTION OF THE HEAD AND NECK. 




The Levator Palpebr^ Muscle, Fig. 23 (4), arises from 

the roof of fhe orbit in front of 
tlie optic foramen. It wridens 
as it extends forwards, and is 
inserted bj a broad tendon 
into the upper margin of the 
superior tarsal cartilage. 

The Superior Oblique 
Muscle, Fig. 23 (5), arises 
from the inner part of the op- 
tic foramen, passes along the 
inner and upper part of the 
orbit to the cartilaginous pul- 
ley, through which its tendon 
passes to be reflected down- 
wards, backwards, and out- 
wards to the ball of the eye. 
The reflected portion of this 
muscle must be left for the 
present. 

The Fourth Nerve, or the 
Pathetic, Fig. 20 (4), enters 
the orbit above, and on the 
inner side of the frontal, which it leaves in the posterior part 
of the orbit, passing inwards to the superior oblique muscle, 
which it penetrates by several filaments on the orbital side. 

The Lachrymal Nerve, Fig. 37 (10), enters the orbit a 
little to the outside of, and below the frontal nerve, and above 
the muscles, runs along the upper border of the external 
rectus to the lachrymal gland, to which it sends filaments ; 
after perforating or passing beneath the gland, it divides into 
palpebral branches. One of these anastomoses with a branch 
of the facial, one goes to the integument upon the forehead, 
and one or two filaments pass downwards to join the second 
division of the fifth pair. 

These parts may now be divided in the anterior portion of 
the orbit, and reflected back. As the levator palpebrse is 
turned back, a branch of the third nerve, or motor oculi, will 
be seen entering it on its under surface. The nerves above 
described should all be preserved for the purpose of tracing 
them through the cavernous sinus. 



The Neeves in the Orbit above the 
Muscles, brought into View by re- 
moving the roof of the Orbit and 
THE Periosteum. — 1. Fifth nerve. 2. 
Ophthalmic branch of same nerve. 3. 
Third nerve. 4. Fourth nerve. 5. Optic 
nerve. 6. Sixth nerve, a. Internal ca- 
rotid artery. 



APPENDAGES OF THE EYE WITHIN THE OEBIT. 93 



The Superior Eectus Muscle, Fig. 23 (9), is now seen in 
the central part of the orbit. It arises from the upper and 
outer part of the optic foramen, and passes forwards to be 
inserted into the sclerotic coat of the eyeball, near its junction 
with the cornea. This is to be divided near its insertion, and 
turned back, observing at the same time the branch of the 
motor oculi nerve, which penetrates its under surface. Be- 
neath the superior rectus, and between the external and in- 
ternal recti muscles, is the most intricate part of the anatomy 
of the orbit. The areolar and adipose tissue found here must 
be gradually and cautiously removed. 

The Kasal Kerve, Fig. 21, with the ophthalmic artery and 
vein, crosses the optic nerve 



from without inwards. As 
this nerve enters the orbit 
between the two heads of the 
rectus externus, it usually 
sends a small twig to the 
lenticular ganglion, and just 
as it passes over the optic 
nerve, gives off' three or four 
ciliary branches, which ac- 
company that nerve on its 
inner side to perforate the 
sclerotic coat. The nasal 
nerve then continues its 
course to the inner part of 
the orbit, and forwards as 
far as the anterior ethmoidal 
foramen, where it divides 
into an external and inter- 
nal nasal branch. The in- 
ternal nasal passes through 
this foramen, and after run- 
ning a short distance on the 
cribriform plate of the eth- 
moid bone, enters the nose 



Fig. 21. 




The Deep Nerves op the Oubit seen 

PROM above by removing THE BoNE AND 
DIVIDING THE ElEVATOR OF THE UpPER 

Eyelid and the Upper Rectus Muscle. 
— a. Internal pterygoid muscle, h. Tem- 
poral muscle, c. Cut surface of bone. d. 
Elevator of the eyelid and upper rectus 
muscle. c. Carotid artery. 1. Optic 
nerve. 2, Fifth nerve. 3, Ophthalmic 
nerve. 4. Third nerve. 6. Sixth nerve. 



through a small foramen at 

the side of the crista s^alli, 

then continues in a groove on the inner surface of the nasal 

bone to its lower border, where it leaves the nasal cavity 



94 DISSECTION OF THE HEAD AND NECK. 

to be distributed to tbe integument covering tlie ala of tbe 
nose. 

The external nasal^ or infra-trochlear^ goes to the anterior 
and inner part of tbe orbit, beneath the tendon of the supe- 
rior oblique, where it divides into filaments to supply the 
integument of the upper part and side of the nose, the upper 
eyelid, and lachrymal sac. 

The Lenticular Ganglion, Fig. 22 (s), is a small reddish 
body, situated between the optic nerve and external rectus 
muscle, about half an inch behind the ball of the eye. Its 
size and shape vary in different subjects. Behind, it receives 
a filament from the nasal and the lower division of the motor 
oculi, and is usually connected with the sympathetic by a 
branch from the cavernous sinus. Anteriorl}^ it sends off 
eight or ten ciliary branches^ which pass along the outer and 
under part of the optic nerve to perforate the sclerotic coat. 
This small ganglion may readily be found by tracing one of 
the ciliary nerves backwards to its origin. 

The Ophthalmic Aetery, a branch of the internal carotid, 
arises near the anterior clinoid process, and enters the orbit 
through the optic foramen, behind and exterior to the optic 
nerve, and crosses it to reach the nasal nerve, which it accom- 
panies to the inner and anterior part of the orbit, where it 
divides into its terminating branches. The following are 
branches of this artery : — 

The lachrymal hranch arises between the superior and ex- 
ternal recti muscles, but soon joins the lachrymal nerve, and 
accompanies it to the lachrymal gland, which it supplies. It 
also sends branches to the upper eyelid, to the conjunctiva, 
and one which perforates the malar bone to anastomose with 
the deep temporal arteries. It sometimes anastomoses with 
the middle meningeal. 

The central artery of the retina penetrates the optic nerve 
about half an inch behind the eyeball, which it enters 
through the porus opticus, to be distributed to the retina 
and hyaloid membrane (Fig. 21). 

The supra-orhital arises beneath the superior rectus, and 
passes upwards and forwards on the inner side of this muscle 
and the levator palpebrse, joins the supra-orbital nerve, and, 
with it, goes to the forehead, sending a small branch to the 
frontal bone. 



APPENDAGES OF THE EYE WITHIN THE OEBIT. 95 

The ciliary arteries consist of three sets ; the anterior, which 
are irregular in their origin, perforate the sclerotic coat about 
two lines behind the margin of the cornea; the long and 



Fig. 22. 




A View op the Third, Fourth, and Sixth Pairs of Nerves. — 1. Ball of the 
eye, the rectus externus muscle being cut and hanging down from its origin. 2. 
The superior maxilla. 3. The third pair, or motor oculi, distributed to all the mus- 
cles of the eye except the superior oblique and external rectus. 4. The fourth pair, 
or pathetic, going to the superior oblique muscle. 5. One of the branches of the 
fifth. 6. The sixth pair, or motor externus, distributed to the external rectus mus- 
cle. 7. Spheno-palatine ganglion and branches. 8. Ciliary nerves from the len- 
ticular ganglion, the short root of which is seen to connect it with the third pair. 

short posterior arise a little distance behind the ball of the 
eye ; the short, ten or fifteen in number, accompany the ciliary 
nerves; the two long ones perforate the sclerotic coat, one on 
either side of the optic nerve, and a little farther from it than 
the short. 

The muscular hranches are divided into the superior, which 
go to the superior rectus, oblique, and levator palpebral ; and 
the inferior, which are distributed to the other recti muscles, 
and inferior oblique, and from which are derived some of the 
anterior ciliary arteries. 

The ethmoidal hranches pass through the anterior and poste- 
rior ethmoidal foramina, and give branches to the dura mater 
and upper part of the nasal fossae. 

There arc two ^mlpehral hranches; the superior, wliicli enters 
the upper lid near the inner angle and anastomoses with the 



96 DISSECTION OF THE HEAD AND NECK. 

lachrymal; the inferior, which descends behind the tendon 
of the orbicularis to the lower lid, and anastomoses with the 
infra-orbital. 

The nasal artery runs over the tendon of the orbicularis to 
the integument covering the side of the nose, and anasto- 
moses with the facial. The frontal goes to the muscles and 
integument of the forehead. 

The Optic ISTekye enters the orbit through the optic fora- 
men, and proceeds to the ball of the eye, which it enters just 
inside of its axis. As it passes through the optic foramen, 
it receives an investment from the dura mater, which leaves 
it again to become continuous with the sclerotic coat. 

The Ophthalmic Yein, Fig. 19, c, is formed by branches 
corresponding to the arteries in the orbit. It leaves the orbit 
between the two heads of the rectus externus, passing through 
the sphenoidal fissure to terminate in the cavernous sinus. 
At the inner and anterior part of the orbit, it communicates 
with the frontal and facial veins. 

The vessels and nerves which enter the ball of the eye, and 
which have been examined, may now be detached and turned 
backwards, to facilitate the dissection of the parts in the lower 
portion of the orbit. 

The Internal Eectus Muscle, Fig. 23 (lo), arises from 
the margin of the optic foramen, and passes along the inner 
part of the orbit, to be inserted into the sclerotica just behind 
the cornea. It is partially separated from the eyeball by 
the inferior oblique. A branch of the motor oculi nerve 
enters its ocular surface. 

The External Eectus, Fig. 23 (i i), arises by two heads 
connected by a tendinous arch, beneath which the motor 
oculi and nasal branch of the fifth enter the orbit. It occu- 
pies the outer part of the orbit, and is inserted into the scle- 
rotica in the same manner as the other recti. This muscle 
is supplied by the sixth nerve, or abducens, which enters the 
orbit between the motor oculi and ophthalmic vein, and pene- 
trates the ocular surface of the muscle by several filaments. 

The Inferior Rectus, Fig. 23 (i 3), arises in common with 
the internal rectus and lower head of the external rectus, 
and extends along the lower part of the orbit to the eyeball, 



APPENDAGES OF THE EYE WITHIN THE ORBIT. 97 

into which it is inserted like the other recti. It receives a 
branch from the motor oculi, which enters its ocular surface. 

Fig. 23. 




A View of the Muscles of the Eyeball, taken from the outer side of the 
Right Orbit. — 1. A small fragment of the spheuoid bone around the entrance of 
the optic nerve into the orbit. 2. The optic nerve. 3. The globe of the eye. 4. 
The levator palpebrse muscle. 5. The superior oblique muscle. 6. Its cartilaginous 
pulley. 7. Its reflected tendon. 8. The inferior oblique muscle ; a piece of its bony 
origin is broken off. 9. The superior rectus muscle. 10. The internal rectus, almost 
concealed by the optic nerve. 11. Part of the external rectus, showing its two heads. 
12. The extremity of the external rectus at its insertion, the intermediate portion 
of the muscle having been removed. 13. The inferior rectus muscle. 14. The scle- 
rotic coat. 

The internal and external recti may now be divided within 
a short distance of their insertion, and turned back with the 
nerves supplying them, thus bringing into view the inferior 
oblique^ with the nerve distributed to it. 

The Inferior Oblique Muscle, Fig. 23 (s), arises from the 
inner and anterior part of the floor of the orbit, crosses the 
inferior rectus, between it and the periosteum, and continues 
in a direction obliquely outwards and upwards, between 
the external rectus and the eyeball, to be inserted into the 
sclerotica near the insertion of the superior oblique. The 
nerve to the inferior oblique is the largest branch of the 
motor oculi; it runs along the exterior border of the infe- 
rior rectus, and penetrates the muscle at right angles. This 
branch of the motor oculi is connected by a filament to the 
lenticular ganglion. 

Besides the nerves already mentioned, a branch froni the 
superior maxillary division of the fifth pair enters the orbit 
through the posterior part of the spheno-maxilla;y fissure, 
and divides into the malar and temporal branches. This 
nerve is situated in the lower and outer part of the orbit. 
The malar portion passes through the malar bone, and supplies, 
9 



98 DISSECTION OF THE HEAD AND NECK. 

in part, the orbicularis palpebrarum, anastomosing with the 
facial nerve. The temporal portion^ after receiving a branch 
from the lachrymal nerve, passes through the malar bone to 
the temporal fossa, in which it ascends some distance, then 
perforates the temporal aponeurosis, and is distributed to the 
integument. It anastomoses with the facial in the temporal 
fossa. 

The eyeball may now be removed from the orbit, and the 
attachment of the ocular muscles to the sclerotic coat ex- 
amined. For this purpose, the ball should be distended with 
wax or some other material of sufficient firmness to preserve 
its shape. 

The insertion of the oblique muscles should be studied with 
reference to the axis of the ball, and the manner in which 
they would affect the eyeball when acting alone or in con- 
junction with the recti muscles. They would seem to be 
capable, of resisting the tendency of the recti to sink the eye- 
ball deeper into the orbit, and, at the same time, of steadying 
it when one or two of the recti act separately, as in turning 
the eye in a particular direction. They are evidently in- 
tended to act in conjunction with the recti, rather than by 
themselves. 

The contents of the sphenoidal fissure, the optic foramen, 
and cavernous sinus should now be examined. To do this 
the lesser wing of the sphenoid, with its attachments to the 
body of the bone, must be removed, if not already done. 

The optic foramen is occupied by the optic nerve, with the 
ophthalmic artery, which lies below and outside of the 
nerve. 

The sphenoidal fissure has passing through it the ophthalmic 
vein, the third, fourth, first branch of the fifth, and sixth 
nerves, and a filament from the lenticular ganglion, to the 
carotid plexus of the sympathetic. These are arranged as fol- 
lows : The fourth, the frontal, the superior division of the 
third and the lachrymal nerves, occupy the upper part of the 
fissure, and are situated, in relation to each other, as enume- 
rated, beginning with the fourth on the inner side. Immedi- 
ately below these are the nasal, and the lower division of the 
third, with the sixth beneath them. The ophthalmic vein or 
veins, occupy the lowest part of the fissure. The nasal, third, 
and sixth nerves as they enter the orbit, pass between the 
two heads of the rectus externus. 



THE EYEBALL. 99 

The cavernous sinus^ Fig. 24, contains the same nerves as 
the sphenoidal fissure, before any division has taken place. 
They are situated, except the sixth, between the serous and 
fibrous layers of its upper wall, the third being on the inner 
side, and the ophthalmic on the outer, with the fourth in the 

Fig. 24. 




A Transverse Section of the Cavernous Sinus op the Right Side. — 1. The 
dura mater, splitting to inclose the vessels and nerves. 2. The internal carotid 
artery. 3. The sixth nerve, receiving a branch from the sympathetic. 4. The 
cavernous sinus. 5. The third nerve. 6. The fourth nerve. 7. The ophthalmic 
division of the fifth nerve. 

middle. Between the laminae of the lower part of the sinus is 
the internal carotid artery, with the sixth nerve lying at the 
outside of it. The sixth nerve is here connected with one 
or more filaments from the carotid plexus. Filaments may 
also be traced from this plexus to the other orbital nerves. 
The intercommunicating filaments which exist between these 
nerves in the cavernous sinus constitute the orbital plexus. 



Sect. YII. — The Eyeball. 

The eyeball is the special organ of vision. Its internal 
parts are very delicate and easily destroyed; hence the dis- 
section of it requires careful manipulation. The student 
should not, however, be discouraged if he fails in his first 
attempt; a little perseverance will give him the dexterity 
requisite to expose satisfactorily its minutest parts. The eyes 
of some of the lower animals may be procured for dissection. 
These can be obtained in a fresh condition, and, as they are 
larger, can be dissected with greater facility than the human 
eye. It will be' well to have several on hand at the same 
time, as the beginner, especially, may expect to destroy quite 
a number before he succeeds in a complete dissection. Care 
must be taken that they arc not injured in removing them 
from the orbit. 



100 DISSECTION OF THE HEAD AND NECK. 

The muscles, areolar tissue, and mucous membrane should 
be dissected off from the external surface. This can be done 
best with scissors. 

The eyeball is not a perfect sphere, but seems to consist 
of segments of two globes of different sizes; the posterior 
segment forms about four-fifths of the exterior surface of the 
ball, and the anterior about one-fifth. The antero-posterior 
diameter of the human eye is about eleven lines, and the 
transverse about ten. 

The external tunic constitutes the framework of the eye ; 
gives it form; affords attachments for muscles; allows the 
passage of rays of light to its interior; transmits vessels 
and nerves, and serves to protect its internal, delicate struc- 
tures. This tunic consists of two parts ; the cornea^ which 
corresponds to the anterior segment, and the sclerotica^ which 
corresponds to the posterior segment. 

The Sclerotica, Fig. 25 (i ), is opaque, of a pearly white ap- 
pearance, and perforated by numerous foramina, which should 
be observed before commencing the dissection of the ball. Be- 
hind, and a little to the inner side of its axis, is the entrance of 
the optic nerve, which is funnel-shaped from without inwards. 
This nerve does not pass through a single large opening, but 
through small apertures, and in separate filaments. The term 
lamina crihrosa has been applied to the structure thus per- 
forated. In the centre of this is the porus opticus for the 
transmission of the arteria centralis retince^ Fig. 28 (2). A short 
distance from, and around the entrance of the optic nerve are 
quite a number of small foramina. Fig. 26, for the passage of 
the ciliary nerves and the posterior long and short ciliary 
arteries; the long ciliary arteries enter, one on each side of 
the optic nerve. Just behind the middle of the eye are 
usually four or five apertures for the exit of the venous 
trunks formed by the vasa vorticosa. Near the anterior 
margin of the sclerotica are several other small foramina for 
the transmission of the short anterior ciliary arteries. 

As the optic nerve perforates the sclerotica on the internal 
iside of the axis of the eye, it is considerably nearer to the 
inner than to the outer part of its anterior border. One of 
the eyes provided for dissection should be divided vertically 
through its axis, and everything removed but the cornea 
and sclerotica. The inner surface, the thickness, the struc- 
ture, and the connection of the sclerotica with the cornea can 



THE EYEBALL. 101 

now be examined. Tlie inner surface is smootli, being lined 
with a serous membrane, the tunica serosa^ and is usually of a 

Fig. 25. 




A Longitudinal Section of the Globe of the Eye. — 1. The sclerotic coat. 
2. The cornea. 3. The choroid coat. 4. The ciliary ligament. 5. The ciliary 
processes. 6. The iris. 7. The pupil. 8. The retina. 9. The canal of Petit, 
which encircles the lens. 10. The anterior chamber of the eye, containing aque- 
ous humor. 11. The posterior chamber. 12. The lens inclosed in its proper 
capsule. 13. The vitreous humor inclosed in the hyaloid membrane. 14. A tubu- 
lar sheath of the hyaloid membrane, or canal of Cloquet. 15. The neurilemma of 
the optic nerve. 16. The arteria centralis retina?. 

darkish appearance ; more so anteriorly, on account of pig- 
mentary cells contained in its structure. It diminishes in 
thickness from behind forwards to its anterior border. In 
children of strumous diathesis, the anterior part of it, which is 
known as the white of the eye, is sometimes so thin and 
translucent that it presents a bluish tint from the choroid 
coat showing through it. It is of a dense fibrous structure, 
consisting of white and yellow elastic tissue ; the fibres run- 
ning in every direction. Its great strength may be tested by 
an attempt to tear it in any direction. This unyielding- 
character is the cause of great pain in some diseases of the eye. 
Its connection with the cornea is very firm, requiring 
maceration for some time to effect a separation. The margin 
of the sclerotica is beveled from Avithin outwards, so as to 
overlap the margin of the cornea, which is beveled in the op- 
posite direction. This overlapping reaches a little further 
above and below than at either side, thus causing an appa- 
rent difference in the transverse and vertical diameters of the 

cornea. The external surface of the sclerotica is in relation 

9-x- 



102 DISSECTION OF THE HEAD AND NECK. 

anteriorly with the conjunctiva, with which it is connected by 
loose areolar tissue, except near the cornea; just behind this, 
with the tendons of the muscles of the eye ; and more posterior- 
ly, with fat and areolar tissue ; its internal surface is in appo- 
sition with the choroid coat and ciliary ligament. It is con- 
nected by means of the neurilemma of the optic nerve, with 
the dura mater, and the periosteum of the orbit. 

The Coenea, Fig. 25 (2), is perfectly smooth and transpa- 
rent, being adapted to the transmission of rays of light. It 
consists of the segment of a sphere of about seven lines in 
diameter. 

The two surfaces of the cornea are not exactly parallel, it 
being thicker in the centre than at the margin; hence it acts 
to some extent as a lens. It is composed of the four following 
layers, going from without inwards : The conjunctiva, the pro- 
per cornea, the elastic cornea, and the aqueous membrane. 
The continuation of the conjunctiva over the cornea is proved by 
maceration, by disease, and by the case of animals which shed 
their skins. This layer is composed of cells which contain a 
limpid fluid. The proper cornea consists of from sixty to 
seventy lamellae, connected by a delicate areolar tissue, which 
contains a vapor or fluid. When the lamellae are pressed 
together and this fluid displaced, the cornea is rendered 
opaque until the pressure is removed, and the fluid restored 
to its natural condition. The proper cornea is blended with 
the sclerotica. The elastic cornea is a thin, transparent lamina, 
lining the concave surface of the proper cornea. It is not 
made opaque by maceration or by boiling ; the shape of the 
cornea is said to depend on it. Its margin projects in be- 
tween the sclerotica and ciliary ligament. The aqueous layer 
is a portion of the thin delicate membrane, which lines the 
chambers of the eye, and secretes the aqueous humor. 

After death the cornea becomes flaccid on account of the 
aqueous humor transuding through it. A molecular change 
in the fluid between the lamellae of the proper cornea has 
been supposed to be the cause of the dimness of the eye 
which occurs in the moribund state. The structure of the 
proper cornea is regarded as a modified form of white fibrous 
tissue ; that of the elastic cornea is not well understood. The 
cornea is very sparingly -supplied with bloodvessels and 
nerves ; wounds of it, however, generally heal by the first in- 



THE EYEBALL. KM 

tention. Its liability to disease and injury renders it an ob- 
ject "worthy of special attention to the student. 

Havilig examined the outer tunic of the eye, the dissector 
will proceed to expose the second tunic, which consists of the 
iris, the ciliary ligament, and the choroid coat. This will 
require another eye. Holding the eye in one hand, make an 
incision through the cornea with a sharp scalpel, or puncture 
it with the scalpel near the centre, and insert the point of one 
blade of a pair of scissors through the puncture and cut to 
the margin, taking care to keep the point gently pressed 
against the inner surface of the cornea, so as not to injure 
the iris; having reached the edge of the sclerotic coat, the 
point of the scissors is to be insinuated between it and the 
ciliary ligament, and then between the sclerotic and choroid 
coats back to the posterior part of the eye. Success in mak- 
ing this incision depends mainly on keeping the point of the 
scissors applied to the inner surface of the cornea and sclero- 
tic coat as it glides oyer the iris, the ciliary ligament, and 
choroid coat. 

Two or three more similar incisions are to be made ; then 
seizing one of the sections of the cornea with the forceps, 
reflect it back to its connection with the sclerotica, and then, 
making slight tension, there will be little or no difficulty in 
separating the sclerotica from the ciliary ligament and cho- 
roid coat. The point of a scalpel may be used to facilitate 
its detachment from the ciliary ligament and divide the ves- 
sels which pass through the sclerotica to the choroid coat. 
When the other sections have been turned back in the same 
manner, a beautiful view of the iris, ciliary ligament, and 
choroid coat will be obtained. 

As the aqueous humor has escaped, the iris will rest 
against the lens and ciliary processes, thus obliterating the 
posterior chamber of the eye. The anterior surface of the 
iris, with the pupil in its centre, should be observed ; also 
its attachment to the ciliary ligament. 

The CiLiAKY Ligament, Fig. 26, e, is about a line in width, of 
a light color, and attached anteriorly to the iris ; posteriorly, 
to the choroid coat ; and by its external surface to the sclero- 
tica. It is composed of fibro-ccllular tissue ; it is not vascu- 
lar itselF, although it transmits the ciliary arteries to the iris. 



104 



DISSECTION OF THE HEAD AND NECK. 



The canal of Fontana is a groove situated between the cor- 
nea, sclerotica, and the ciliary ligament. 

Passing over the choroid coat will be seen the ciliary nerves^ 
Pig. 26; and the two long ciliary arteries^ which anastomose 
around the ciliary ligament with each other and with the 
anterior ciliary arteries, forming a circle, from which branches 
are sent into the iris, where another circle is formed. The 
nerves also penetrate the ligament to reach the iris. 

The veins^ Fig. 26, c, in the eye do not accompany the arte- 
ries; they are arranged so as to form, in the outer layer of 
the choroid the vasa vorticosa; these form four or five princi- 



Fig. 26. 




Ciliary NerviSs. — a. Sclerotica, h. Vasa vorticosa. and outer surface of choroid, 
c. One of the chief trunks of the vasa vorticosa as they leave the choroid, d, d. 
Ciliary nerves, e. Annulus albidus, or ciliary ligament. /. Iris. -g. Pupil. 

pal trunks which perforate the sclerotica behind the middle 
of the eyeball. 

The Choroid Coat is perforated behind by the optic 
nerve. Its external surface presents a smooth, shining ap- 
pearance, being covered by the inner layer of the tunica 
serosa. Its color is a jet black. 

Having examined the structures now exposed as far as 
can be done in the present stage of the dissection, the iris 
may be divided with the scissors into three sections, and re- 
flected backwards without breaking up its connection with 
the ciliary ligament. 

The boimdaries of i\iQ posterior chamher^ Fig. 25 (i i), of the 



THE EYEBALL. 105 

eye will now be seen, consisting of tlie iris in front, and the 
lens and ciliary processes behind. That a space does actually 
exist behind the iris, and in front of the lens, which is filled 
with a portion of the aqueous humor, may be proved by 
freezing an eye, when a thin layer or pellicle of ice will be 
found separating these two bodies. 

The anterior chamber^ Fig. 25 (i o), of the eye is the space 
between the concave surface of the cornea and the anterior 
surface of the iris ; it is much larger than the posterior. The 
iris is the only septum between the two chambers, forming 
the anterior boundary of one, and the posterior boundary of 
the other. These chambers communicate with each other 
through the pupil. 

The pupil^ Fig. 26, ^, is an aperture in the iris which ad- 
mits the rays of light into the posterior part of the eye. It 
is not exactly in the centre of the iris, being placed a little 
nearer to its inner than to its outer margin. In the human 
eye it is circular, but in the lower animals varies in shape. 

The Ieis, Fig. 25, 5, and Fig. 26,/, it will be seen, presents 
two borders and two surfaces. The outer border is attached by 
areolar tissue to the ciliary ligament, while the inner is free ; 
the two surfaces are constantly in contact with the aqueous 
humor. It is the iris which gives to the eye its color, as we 
say a person has a ' blue eye,' a ' hazel eye,' or a ' black 
eye.' Its posterior surface is covered with a dark pigment 
called the uvea^ from its resemblance to the color of the grape. 
Different opinions have been entertained in regard to the 
structure of the iris. It has been considered by some as 
composed of an elastic tissue, and by others as consisting of 
muscular fibres arranged in a circular and radiated form ; the 
former consisting of a narrow band around the pupil, and the 
latter extending in a radiated manner to its outer circum- 
ference. It is considerably thicker than the choroid coat, 
and is abundantly supplied with bloodvessels and nerves. It 
responds to the stimulus of light applied to the retina, 
regulating by varying the size of the pupil, the number of 
rays which shall pass through the lens to that tunic. Some 
persons have the power of exciting its contractility by voli- 
tion. The size of the pupil may be increased or diminished 
by medicinal agents, and by certain conditions of the brain, 
as in concussion and compression. 



106 DISSECTION OF THE HEAD AND NECK. 

Daring the early part of foetal life, tlie pupil is occupied by 
a membrane called the memhrana pupillaris ; this, however, 
disappears in the human foetus about the seventh month, but 
in some of the lower animals continues some days after 
birth. 

The iris should now be detached from the ciliary ligament, 
and the position of the lens and the ciliary processes sur- 
rounding it, carefully noticed. The view presented in this 
stage of the dissection is important, as the student can now 
obtain a distinct idea of the relative position of the lens to 
the anterior border of the sclerotic coat, and be able to un- 
derstand the connection which exists between it and the 
framework of the eye, as well as the manner in which, by 
means of this connection, it is kept in its place. 

To separate the choroid coat from the retina, a small open- 
ing is to be made through it, near the posterior part of the 
eye. This may be done by detaching it with the point of the 
scalpel, being careful not to injure the retina beneath it. 
When the opening is made, the choroid coat may be easily 
removed by using two pairs of forceps, cutting away with 
the scissors, from time to time, portions of it which have 
been detached. In dissecting off this coat, it may be found 
convenient to place the eye in a shallow vessel containing 
water. 

The Choeoid Coat, Fig. 26, 5, is composed of three layers, 
an external or venous^ a middle or arterial (membrana Ruy- 
schiana), and an internal or pigmentary layer. It extends 
anteriorly to the ciliary ligament and ciliary processes, with 
which it is intimately connected. Its inner layer consists of 
six-sided cells, which contain a granular substance. In some 
animals, the inner surface of the choroid coat presents poste- 
riorly a beautiful metallic lustre, known as the tapetum. 

As the choroid coat is removed, a layer of areolar tissue 
may be seen next to the retina ; this is the memhrana Jacohi; 
by some it is regarded as forming the outer layer of the re- 
tina. Sometimes it is with difficulty that this membrane can 
be exposed so as to allow of its demonstration, even as floc- 
culi floating in water ; at other times it may be distinctly seen. 
As we approach the anterior border of the choroid coat, in 
the process of removing it, the termination of the nervous 
layer of the retina anteriorly will be observed; and also, in 
front of it, the ciliary processes, proceeding to join the hyaloid 



THE EYEBALL. 



107 



Fig. 27. 



processes aronnd the margin of the lens. The view now ob- 
tained of the ciliary processes from behind, in connection 
with the one from the posterior chamber, will afford a very 
accurate idea of their exact position in the eye. They form 
a sort of septnm between the anterior border of the retina 
and the posterior chamber, while they establish a connection 
between the lens and the sclerotic coat through the ciliary liga- 
ment on the one hand, and the hyaloid processes on the other. 

The Ciliary Processes, Fig. 27 (4), from sixty to seventy 
in number, are an interesting portion of the mechanism of the 
eye. The student will do well to study them faithfully; they 
are, as he will see, directly 
connected with, or related to, 
nearly all the other parts of 
this organ. Externally, they 
are in relation with the ciliary 
ligament, the choroid coat and 
iris; internally, with the hy- 
aloid processes ; anteriorly, 
with the posterior chamber; 
and posteriorly, with the re- 
tina. They are regarded by 
some as being composed of 
muscular tissue^ and capable of 
acting on the lens through 
their connection with the hya- 
loid processes. In this case, 
their fixed attachment would 
•be to the ciliary ligament, and 
through it to the sclerotica. 

The Retina, Fig. 25 (s), is 
composed of three layers: the 
membrana Jacobi, the nervous, and the vascular layer. 

The membrana Jacohi is considered by some a serous 
membrane. It is more intimately connected with the retina 
than with the choroid coat. It seems to consist of cylin- 
drical cells, varying in length, and arranged vertically or 
obliquely to the surface of the membrane. To expose it the 
choroid should be r^noved from behind. 

The nervous layer consists of a soft pulp}^ substance, re- 
garded by some as an expansion of the ncurine contained 




The Anterior Segment of a 
Transverse Section op the Globe 
OF THE Eye, seen from within. — 1. 
The divided edge of the three coats — 
the sclerotic, choroid, and retina. 2. 
The pupil. 3. The iris; the surface 
presented to view in this section being 
the uvea. 4. The ciliary processes. 5. 
The anterior border of the retina. 



108 



DISSECTION OF THE HEAD AND NECK. 



Fig. 28. 




in the tubes of the optic nerve. It loses its transparency 

soon after death. In the human eye its anterior border is 

serrated. 

The vascular or inner layer 
is composed principally of a 
network of vessels proceeding 
from the central artery of the 
retina. It is exposed by ma- 
cerating an eye for two or 
three days, and then scraping 
off the nervous layer. It ter- 
minates anteriorly by passing 
in between the ciliary and 
hyaloid processes. This layer 
is intended for the ramifica- 
tion of vessels to supply the 
retina and hyaloid membrane, 
also to fix and support the 
nervous layer. 

The nervous substance of 
the retina is deficient in a 
small spot, about a line from 
the entrance of the optic nerve 
and in the axis of the eye ; 
this has been called the fora- 

teus which surrounds it. X'k fold of men of Sommenng^ Fig. 28 (4). 

the retina, which generally obscures rp]^Q Umhus luteUS is a ycUoW 

the foramen of Sommermg after the , t ,i • i • 

eye has been opened. Spot around thlS depression Or 

foramen. These points Id the 
retina are best seen when a transverse vertical section of 
the eyeball has been made. In this section the retina is 
commonly thrown into folds by being deprived of the sup- 
port of the vitreous humor. 

The Hyaloid Membeane, or capsule, contains the vitreous 
humor ^ Fig. 25 (i 3), which occupies about three-fourths of the 
eyeball posteriorly. It is a thin, delicate, transparent mem- 
brane, consisting of a general capsule and a large number of 
septa projecting from its inner surface, so as to form numer- 
ous small cells or compartments. These cells communicate 
with each other, as is shown by the gradual escape of the 
humor when the vitreous body is cut or punctured. The 
hyaloid hody^ which includes the hyaloid membrane and the 



The Posterior Segment of a 
Transverse Section of the Globe 
OF the Eye, seen from within. — 1. 
The divided edge of the three coats — 
the membrane covering the whole in- 
ternal surface is the retina. 2. The 
entrance of the optic nerve with the 
arteria centralis retinae piercing its 
centre. 3, 3. The ramifications of the 
arteria centralis. 4. The foramen of 
Sdmmering; the shade from the sides 
of the section obscures the limbus lu- 



THE EYEBALL. 



109 



vitreous humor, is traversed in the centre bj a canal, called 
the canal of Gloquet^ Fig. 25 (14), for the transmission of a 
branch of the central artery of the retina. This artery 
assists in nourishing the hyaloid membrane, and, probably, 
the lens. 

]N'ear the margin of the lens the hyaloid membrane 
divides into two layers, one of which passes in front, and 
the other behind it. Between these two layers and the 
margin of the lens is a series of cells, constituting what has 
been called the canal of Petit, Fig. 25 (9). These cells may 
be demonstrated by inflating them with a fine blowpipe. 

Just behind the canal of Petit, the hyaloid membrane is 
somewhat thickened, and presents folds or plic^, named the 
hyaloid processes. These processes are received into grooves 
between the ciliary processes. When the latter are removed, 
the former with the pigment adhering to them form the 
zonula of Zinn, The vitreous body is in relation with the 
retina, the ciliary processes, and the lens, which is partly 
embedded in it. The vitreous humor is composed of water 
and about two per cent, of saline substances in solution. 



Fig. 29. 



Fig. 30. 




A Side View of thk Adult 
Lens. — 1. Its anterior face. 2. Its 
posterior face. 3, 3. Its circumfer- 
ence. 




Trtple Division op the Lens 
AND THE Course of its Fibres. 



The Crystalline Lens, Fig, 29, is placed between the 
vitreous and aqueous humors. Its posterior surface is more 
convex than the anterior; but, in tliis respect, it varies in 
different eyes, and at ditl'erent periods of life; in the il\)tus 
it is spheroidal, becoming more ilattcned as age advances. 

It has a capsule which resembles in structure the elastic 
10 



110 



DISSECTION OF THE HEAD AND NECK. 



layer of the cornea. This is thicker in front than behind. 
Its inner surface does not adhere to the lens, which escapes 
readily when the capsule is divided. Behind, it is connected 
to the hyaloid membrane by delicate areolar tissue. "When 
it is punctured some time after death, a fluid escapes ; this 
does not probably exist previous to death ; it is called the 
liquor Morgagni. 

The lens increases in density from the exterior surface 



towards the centre, which is called the 



Fig. 31. 



nucleus. Its transverse diameter is 
about four lines; its antero-posterior 
about two ; its weight is between three 
and four grains. When boiled in 
water, or immersed in dilute acid, it 
separates, into concentric lamellae, 
and also by slight pressure into three 
triangalar segments, Fig. 31, the bases 
of which correspond to its circumfer- 
ence. Its minute structure is not 
well understood. It consists chemi- 
cally of water, albumen, salts, and an 
extractive matter. 

The aqueous humor is contained in 

the anterior and posterior chambers 

of the eye. Its weight is about five 

grains. Its composition is the same as that of the vitreous 

humor. Both surfaces of the iris are bathed by it. 




Lens hardened in spirit 
and partially ditided 
along the three interior 
planes, as well as into 
Lamella. — Magnified 3i di- 
ameters. 



Sect. YIII. — Spheno-maxillaky Eegion. 



Before commencing the study of this region, that portion 
of the cranium which is involved in its dissection should be 
carefully examined. The following are the parts which re- 
quire special attention: The ramus of the inferior maxilla 
with its cor on old and condyloid processes, and the posterior 
dental foramen ; the spheno -maxillary fissure and infra-orbital 
canal ; the ptery go-maxillary fossa, or the space between the 
pterygoid process of the sphenoid and tuberosity of the supe- 
rior maxilla, together with the vidian, palatine, spheno- 
palatine, and round foramina, which open into it ; also the 
foramina ovale and spinosum, which are situated behind the 
base of the pterygoid process. 



SPHENO-MAXILLARY REGION. Ill 

The portions of the skull concerned in this dissection may be 
arranged in three planes : First, the zygoma with the super- 
ficial portion of the malar bone. Second, the external portion 
of the superior maxilla, the glenoid cavity, and eminentia 
articularis of the temporal bone, and that part of the greater 
wing of the sphenoid situated in the zygomatic fossa. Third, 
the tuberosity of the superior maxilla, with the pterygoid 
process, and the horizontal portion of the great wing of the 
sphenoid. 

The Masseter muscle, Fig. 61 (le), which was noticed in 
the superficial dissection of the face, should now be more 
accurately observed. It is a powerful muscle, consisting of 
two parts, an external and an internal. The externalis the 
largest ; it arises, chiefly tendinous, from the anterior portion 
of the zygomatic arch, and the malar process of the superior 
maxilla, passes downwards and backwards, and is inserted 
into the lower half of the ramus of the inferior maxilla, 
extending as far back as the angle. The internal portion 
arises from the posterior part of the arch ; its fibres pass 
downwards, most of them in a vertical direction, and are 
inserted into the upper half of the ramus of the lower jaw. 
The lower portion of the internal is overlapped by the fibres 
of the external. When both masseter muscles act, they 
approximate the lower jaw to the upper; when the exter- 
nal portions alone act, they move it forwards ; and when 
the internal portions act, they draw it backwards. By 
acting separately, they can move the jaw laterally. The 
masseter may now be removed. In doing this, the masseteric 
artery and nerve should be sought ; the former is a branch of 
the internal maxillary, and the latter, of the second division 
of the fifth pair. They penetrate the internal surflice of the 
muscle, just above the sigmoid notch, where they may be 
easily found. 

The masseter having been removed, the zygomatic arch 
and the contiguous portion of the malar bono may now be 
cut away, thus exposing the hiscrtion and lower part of the 
temporal muscle, which was described with the soft parts on 
the outside of the cranium. 

The coronoid process should now be cut through, and 
turned upwards with the temporal muscle, care bouig taken 
not to injure the parts beneath. In doing this, the dccj.^ 



112 



DISSECTION OF THE HEAD AND NECK. 



temjrjoral arteries^ Fig. 33 (i 7, 1 s), and nerves^ Fig. 37 {ji2\ will 
be seen penetrating the internal surface of the muscle. Each 
consists of an anterior and posterior branch, the artery being 
derived from the internal maxillary, and the nerve from the 
third division of the fifth pair. A branch of the superior 
maxillary nerve may also be seen passing through the outer 
wall of the orbit, and penetrating the mnscle in the anterior 
part of the fossa. 

The inferior maxilla should now be divided transversely 
through the base of the condyloid process, and vertically 
through the body in a line corresponding to the last molar 
tooth. In doing this, both the saw and chisel may be advan- 
tageously employed. Before cutting through the condyloid 
process, the masseteric artery and nerve should be traced to- 
ward their origin and pushed away. 

If the section of bone between the tAVO incisions be care- 
fully turned outAvards and backwards, without detaching it 
from the structures beneath, the following parts will be ex- 



Fig. 32. 



The Ptertgoideus Exteexus, Eig. 32 (1), situated in the 
upper part of this region, arises by two heads, the upper and 
smaller, from the great Aving of the sphenoid, near the root of 

the pterygoid process, the lower 
one from the outer plate of the 
pterygoid process. These two 
heads pass horizontally out- 
wards, and unite to be inserted 
by a short tendon into the neck 
of the condyle of the lower jaw, 
the internal lateral ligament and 
the interarticular cartilage. 

The internal maxillary artery, 
Eig. 33 (1 2), crosses over the ex- 
ternal surface of this muscle from 
its lower border near the con- 
dyloid process, to the pterygo- 
maxillary fossa. The masse- 
teric nerve passes over its 
upper margin from within out- 
wards, and in its course sends 
a small branch to the temporo- 




The two Pterygoid Muscles. 
The Zygomatic Arch and the 

GREATER PART OF THE RamUS OF 

THE Lower Jaw have been re- 
moved, IN ORDER TO BRIXG THESE 

Muscles into view. — 1. The sphe- 
noid origin of the external pterygoid 
muscle. 2. Its pterygoid origin. 3. 
The internal pterygoid muscle. 



SPHENO-MAXILLARY EEGION. 118 

maxillary articulation. The buccal nerve usually arises by 
two roots, which unite after perforating the pterygoideus 
externus; it then runs downwards and forwards over this 
muscle to the buccinator ; at the anterior border of the 
masseter it becomes superficial, and is distributed to the 
buccal portion of the face. The posterior deep temporal 
artery i^ the first part of its course runs on this muscle ; also 
the buccal artery. 

The Pteeygoideus inteenus. Fig. 32 (3), is situated deeper 
and lower down than the externus. It arises from the pterygoid 
fossa, and passes downwards and somewhat backwards, and is 
inserted into the internal surface of the angle and ramus of 
the lower jaw. In form it resembles the masseter. The 
pterygoid muscles, when they act on both sides, draw the jaw 
forwards and upwards ; and when they act on one side only, 
they move the jaw laterally, as in grinding the food. 

The lingual hranch^ Fig. 37 (23), of the inferior maxillary 
nerve will be seen crossing this muscle in a direction from 
above downwards. The chorda tympani joins the lingual at 
the posterior border of the muscle, having come from the 
glenoid fissure to this point, along the deep surface of the 
external pterygoid. 

The myh-hyoid branch, Fig. 87 (ss), of the inferior dental 
nerve, with a small artery accompanying it, is situated close 
to the inner surface of the inferior maxilla, being frequently 
lodged in a groove in the bone just above the insertion of 
the pterygoideus internus. 

The pterygoideus externus may now be dissected away so 
as to expose the following branches of the internal maxillary 
artery, and inferior maxillary nerve, and the posterior dental 
branch of the superior maxillary nerve. The main trunk 
of the artery should first be traced to the pterygo-maxillary 
fossa. The chorda tympani will be seen crossing the artery 
almost at right angles to join the lingual nerve. The infe- 
rior dental artery, Fig. SS (14), and neri^e, Fig. 87 (24), may be 
easily found as they enter the posterior dental foramen, and 
traced from this point to their origin. 

The inijlo-hyoid nerve comes from the dental just before it 
enters the foramen. The middle meningeal artery passes up- 
wards and forwards to the foramen spinosum, through which 
it enters the cavity of the cranium. It passes between two 

10-^- 



114 



DISSECTION OF TPIE HEAD AND NECK. 



roots of the temporo-auricular nerve^ whicli passes backwards 
and upwards between the cervix of the pondyle and the 
auditory meatus, giving off branches to anastomose with the 
facial, to ascend over the zygoma to the temporal region, 
to the meatus and tympanum, and also to the articulation 
and the parotid gland. 

Fig. 33. 




A View of the iNTERNAii Maxillary Artery, as giveit by Sections of 
THE Bones op the Head and Face. — 1. Primitive carotid artery. 2. External 
carotid. 3. Internal carotid. 4. Section of the superior thyroid artery. 5. Point 
where the facial artery crosses the lower jaw. 6, Inferior coronary artery. 7. Su- 
perior coronary artery. 8. Point of anastomosis of facial with the nasal branch of 
ophthalmic. 9. The occipital artery. ]0. Posterior auricular. 11. Temporal ar- 
tery. 12. Origin of the internal maxillary artery. 13. Meuingea magna of the 
dura mater ramifying over its surface. 14. Inferior dental artery in the alveolar 
processes of the lower jaw. 15. The pterygoid arteries. 16. The masseteric arteries. 
17. Deep-seated posterior temporal artery. 18. Deep-seated anterior temporal ar- 
tery. 19. Buccal arteries. 20. Infra-orbital. 21. Posterior palatine. 22. Origin 
of the pterygoid artery. 23. Origin of the spheno-palatine. 

The tympanic artery goes through the Glaserian fissure to 
the tympanum. The pterygoid hranches^ irregular in their 
origin, penetrate the internal surface of the pterygoid mus- 
cles. The anterior meningeal artery arises a little in advance 
of the middle meningeal, and passes through the foramen 
ovale to the dura mater. The deep temporal, masseteric, and 



SPHENO-MAXILLAEY REGION. 



115 



buccal brandies liave already been seen. The superior dental 
and infra-orbital come off jnst before tlie main trunk enters 
the pterygo-maxillary fossa. The superior dental branch 
penetrates the tuberosity of the superior maxilla to be dis- 
tributed to the molar and bicuspid teeth. The infra-orbital 
passes through the posterior part of the spheno-maxillary 
fissure to enter a canal in the floor of the orbit. The re- 
maining branches of the internal maxillary artery cannot 
be seen at this stage of the dissection. The internal maxil- 
lary vein corresponds with the artery and its branches. It 
communicates with the cavernous sinus and the facial vein. 
The posterior superior dental nerve arises from the superior 
maxillary in the posterior part of the spheno-maxillary fis- 
sure, and runs some distance on the tuberosity of the supe- 
rior maxilla, which it penetrates to reach the molar teeth. 

The Temporo -Maxillary Articulation should now be 
examined, so that the structures connected with it may 
be removed. They consist of an external and an internal 
lateral ligament, a capsular ligament, an interarticular fibro- 
cartilage, and two synovial sacs. 

The External Lateral Ligament, Fig. 34 (5), arises from 
the tubercle of the zygomatic 
process of the temporal bone, Fig. 34. 

and is inserted into the outer 
part of the cervix of the con- 
dyle of the lower jaw. 

The Internal Lateral 
Ligament, Fig. 35 (4), arises 
from the spinous process of 
the sphenoid bone, passes 
downwards and forwards to 
be inserted into the inner 
border of the posterior dental 
foramen. It is longer than 
the external, and is separated 
from the bone by the internal 
maxillary artery, and the in- 
ferior dental nerve and ar- 
tery, thus preventing the in- 
ternal pterygoid muscle from pressing upon thorn when 




An Exteunal View of the Auticu- 
LATioN OF THE LowKR Jaw. — 1. Tlio zy- 
gomatic arch. 2. The tuborclo of the 
zygoma. 3. The ramus of the lower jaw. 
4. The mastoid portion of the temporal 
bone. 5. The external lateral ligament. 
6. The stylo-maxillary ligament. 



116 



DISSECTION OF THE HEAD AND NECK. 



contracting. 



Some of its fibres wMcli adhere to the cap- 
sule have been designated the short internal lateral liga- 
ment. 



Fig. 35. 




An Internal View of the Articula- 
tion OF THE Lower Jaw. — 1. A section 
through the petrous portion of the temporal 
bone and spinous process of the sphenoid. 
2. An internal view of the ramus, and part 
of the body of the lower jaw. 3. The in- 
ternal portion of the capsular ligament. 
4. The internal lateral ligament. 5. A 
small interval at its insertion, through 
which the mylo-hyoid nerve passes. 6. 
The stylo-maxillary ligament, a process of 
the deep cervical fascia. 



The Capsular Ligament arises principally from the 
articular eminence and glenoid fissure, and is inserted into 

the neck of the condyle. It 
^^" ' adheres closely to the interarti- 

cular fibro-cartilage, and keeps 
it in place. In front there is a 
deficiency in it for the insertion 
of the external pterygoid mus- 
cle. 

The Intekarticular Fi- 
bro-Cartilage, Fig. 36 (3, e), 
is placed between the glenoid 
cavity and the condyle of the 
In THIS Sketch A section HAS BEEN jaw, dividing thisspacc into 

carried through the joint, in or- " ■ - - - 

DER TO show the NATURAL POSITION 
OF THE INTERARTICULAR PIBRO-CARTI- 
LAGE, AND THE MANNER IN WHICH IT 
IS ADAPTED TO THE DIFFERENCE OF 
FORM OP THE ARTICULATING SURFACES. 

1. The glenoid fossa. 2. The eminen- 
tia articularis. 3. The interarticular 
fibro-cartilage. 4. The superior syno- 
vial cavity. 5. The inferior synovial 
cavity. 6. An interarticular fibro- 
cartilage, removed from the joint, in 
order to show its oval and concave 
form ; it is seen from below. 




two cavities. It is elongated 
transversely. Its margins are 
blended with the ligaments sur- 
rounding the joint, and in front 
with the tendon of the external 
pterygoid muscle. 



There are two Synovial 
Membranes, Fig. 36 (4, 5), 
which line respectively the pa- 
rietes of the two cavities of this 
joint, the superior being the larger. The interarticular fibro- 
cartilage is sometimes deficient in the centre, in which case 



SPHENO-MAXILLAEY REGION. 117 

the two sacs may commiinicate with each other. This artic- 
ulation should be studied with reference to luxation, and 
the action of the masticatory muscles. 

The Stylo-Maxillary Ligament, Fig. 34 (e), arises 
from the styloid process, and is inserted into the angle of 
the lower jaw, furnishing an attachment for a reflection of 
the deep cervical fascia, and for a part of the stylo-glossus 
muscle. 

The Pterygo -Maxillary Ligament is attached above to 
the external wing of the pterygoid process, and below to the 
base of the coronoid process of the lower jaw. The buccinator 
arises in part from its anterior, and the superior constrictor 
of the pharynx from its posterior border. 

The remaining portion of the malar bone, with the malar 
process of the maxilla, and that part of the great wing of the 
sphenoid which forms the posterior boundary of the spheno- 
maxillary fissure, should now be removed, so as to expose 
the upper part of the pterygo-maxillary fossa. The infra- 
orbital nerve and artery may now be traced into and through 
the infra-orbital canal. The roof of this canal may be best 
cut away with a small sharp chisel. If the nerve be slightly 
raised in the canal, the anterior dental branch will be seen 
leaving it to enter the antrum Highmori. Two or three fila- 
meats also leave it to go to the mucous membrane lining the 
antrum. The infra-orbital nerve. Fig. 37 (7), may now be 
traced back to the foramen rotundum, in doing which the 
origin of the posterior dental and orbital branches should be 
sought. The former consists of two branches, a superior and 
an inferior; the latter enters the orbit and divides into the 
malar and temporal branches. The infra-orbital artery has 
the same course and distribution as the nerve. The infra- 
orbital vein communicates with the flicial by means of the 
alveolar. 

The upper and outer wall of the antrum may now be cut 
away to follow the dental arteries and nerves in their dis- 
tribution. To trace these nerves in their minute ramifications, 
a fresh bone, softened in diluted nitric or muriatic acid, should 
be used. 

The posterior superior dental nerve^ Fig. 37 (7), enters the 
upper part of the antrum, and anastomoses with the posterior 
inferior, and anterior dental nerves. 



118 



DISSECTION OF THE HEAD AND NECK. 



The jiosterioT inferior enters the bone lower down, and 
divides into filaments which go to the molar and bicuspid 
teeth. 

The anterior dental nerve^ Fig. 37 (i s), which enters from the 
infra-orbital canal, passes at first horizontally and then down- 
wards in the anterior wall of the antrum ; it sends filaments 
to the cuspid and incisor teeth, and also to the bone, and 
the lower meatus of the nose. 



Fig. 37. 




A VIEW OF THE DISTRIBUTION OP THE TRIFACIAL OR 5tH PAIR. — 1. Orbit, 2. 

Antrum of High more, 3. Tongue. 4. Lower maxilla. 6. Root of 5th pair, forming 
the ganglion of Gasserius, 6, 1st branch, ophthalmic, 7. 2d branch, superior maxil- 
lary, 8. 3d branch, inferior maxillary, 9. Frontal branch, dividing into supraorbital 
and frontal at 14, 10, Lachrymal branch, dividing before entering the lachry- 
mal gland. 11, Nasal branch. Just under the figure is the long root of the lenticular 
or ciliary ganglion, and a few of the ciliary nerves, 12, Internal nasal, disappearing 
through the anterior ethmoidal foramen. 13. External nasal, 14. Supra orbital 
and frontal, 15. Infra-orbital nerve, 16. Posterior dental branches. 17. Mid- 
dle dental branch. 18, 'Anterior dental nerve. 19, Terminating branches of 
infra-orbital, called labial and palpebral. 20. Subcutaneus malas, or orbital branch. 
21, Pterygoid or recurrent, from Meckel's ganglion. 22. Five anterior branches of 
3d branch of 5th, being nerves of motion, and called masseteric, temporal, pterygoid 
and buccal, 23, Lingual branch joined at an acute angle by the chorda tympani. 
24, Inferior dental nerve terminating in, 25. Mental branches. 26. Superficial tem- 
poral nerve. 27. Auricular branches. 28. Mylo-hyoid branch. 



SPHENO-MAXILLARY EEGION. 119 

The Ganglion of Meckel, or Spheno-Palatine G-ang- 
LION, may now be examined, with its communicating branches. 
For this purpose the upper part of the posterior wall of the 
antrum may be removed, with enough of the great wing of 
the sphenoid fairly to expose the foramen rotundum. If we 
now divide the infra-orbital nerve, and turn it backwards, we 
shall observe two small filaments going downwards to join a 
small reddish mass, of a somewhat triangular shape, which is 
the ganglion of Meckel. The following nerves may be dis- 
covered proceeding from it in different directions : — 

The Spheno-Palatine leaves it on the inner side, and 
passes almost immediately through the spheno-palatine fora- 
men to enter the nose just behind the superior meatus, where 
it divides into branches which will be described with the 
nasal cavity. 

The Palatine Nerve, consisting sometimes of two or 
three divisions, leaves it on the lower side, and enters the 
palatine canal to divide into an anterior^ Tniddle and posterior 
branch. The anterior is distributed to the roof of the mouth ; 
the middle and posterior to the soft palate, the amygdala 
and uvula. The posterior palatine branch not unfrequently 
passes through a separate canal in the palatine bone. 

The Vidian Nerve passes backwards from the ganglion 
to the vidian or pterygoid canal, and through it into the 
cavity of the cranium. It sends several small filaments to 
the sphenoidal sinus. These nerves cannot at present be con- 
veniently followed beyond the pterygo-maxillary fossa. The 
dissection of this ganglion and its nerves, may be made from 
the nasal cavity, by breaking away the vertical plate of the 
palatine bone which forms a septum between the nose and 
the pterygo-maxillary fossa. If the student wishes, he can 
dissect one side of the head as above described, and the other 
side from the nasal cavity. 

As much of the great wing of the sphenoid, with the emi- 
nentia articularis of the temporal bone must now be cut 
away as shall be necessary to expose the foramen ovale. 
Divide the dental and gustatory nerves and turn them up 
towards the foramen ; the otic ganglion will now be observed 
just below the foramen and on the inner side of the inferior 
maxillary nerve. 

The Otic Ganglion is a small, reddish body, like the gan- 



120 DISSECTION OF THE HEAD AND NECK. 

glion of Meckel. It gives off tlie foUo^ving nerves: a fascicu- 
lus, wMch communicates mth tlie inferior maxillary ; ptery- 
goid and auricular branches, tlie latter being a motor and 
the former a sensor filament; and several filaments, which 
connect it with the sympathetic, being sent to the plexus on 
the middle meningeal artery. Two muscular branches also 
leave this ganglion, one supplying the tensor tympani, and 
the other the tensor palati. Posteriorly it gives off the super- 
ficial petrosal nerve^ which perforates the petrous bone to 
join the vidian and a branch from the glosso-pharyngeal in 
the tympanum. This ganglion, like that of Meckel, may be 
reached from within by cutting away the levator palati 
muscle, and finding the cartilaginous portion of the Eusta- 
chian tube, near the osseous extremity of which it is situated. 



Sect. IX. — Dissection of the Eae. 

The oro'an of hearing is divided into the external, middle, 
and internal portions. The first is coA^ered by the skin, the 
second is lined by mucous membrane, and the third has no 
external communication. 

The Exteenal Ear, Fig. 38, is divided into the auricle 
and meatus. The framework of the auricle consists of a 
fibro-cartilage, which gives to it the peculiar form it presents, 
and allows of a great degree of flexibility. It is very firmly 
attached to the margin of the meatus, so much so that the 
weight of the body may be sustained by the auricles. The 
following points are to be noticed upon each auricle : — • 

The cranial surface is, generally convex, while the facial 
surface is concave. The deepest part, that which leads into 
the meatus, is called the concha. The projection in front 
of this, and partly covering it, is the tragus. 'When the 
tragus is pressed inwards, it covers the meatus. Hairs grow 
from its posterior surface. A little lower down, behind and 
opposite to the tragus, is the anti-tragus. This is smaller than 
the tragus, and separated from it by a deep notch called the 
notch of the concha^ or incisura tragica. The anti-helix is the 
ridge which commences just above the anti-tragus, curves 
upwards and forwards to bifurcate, leaving a depression be- 
tween its divisions called the scaphoid, fossa. The external 
curved border of the ear is the helix. The helix is separated 



OF THE EAK. 



121 



Fiff. 38. 



from the anti-helix by the fossa innominata. The lower 
pendulous part of the auricle is the lohe. It consists of a 
duplicature of the skin, with a small portion of adipose sub- 
stance. 

The helix and anti-helix unite behind to form the processus 
caudatus^ which is separated 
from the anti-tragus by a fis- 
sure. The fissure of the tragus 
is situated on its anterior sur- 
face. T\iQ fissure of the helix i^ 
just above the tubercle to which 
is attached the attrahens aurem 
muscle. 

The Ligaments of the auricle 
are intrinsic and extrinsic. The 
former consist of ligamentous 
bands, intended to preserve the 
fibro-cartilage in its proper 
form, and to occupy the fis- 
sures. The latter consist of, a 
posterior^ which connects the 
concha to the mastoid process ; 
an anterior^ which extends from 
the process of the helix to the 
zygomatic arch; and of a liga- 
ment^ which connects the tragus 
to the same part. 

The Intrinsic Muscles, Fig. 
89, of the auricle are the follow- 
ing. The lielicis major is situated 

just above the tragus, on the anterior part of the helix. It 
consists of a narrow band of muscular fibres, tendinous at 
each extremity. 

The helicis minor occupies the helix where it projects into 
the concha. 

The anti-tragicus extends from the external surface of the 
anti-tragus to the processus caudatus. 

The tragicus lies vertically upon tlie external surface of the 
tragus. 

The transversus auriculw is situated on the cranial surface 
of the auricle, extending from the concha to the helix. 
11 




A View op the Left Ear in its 
NATURAL STATE. — 1,2. The Origin and 
termination of the helix. 3, 3. The 
anti-helix. 4. The anti-tragus. 5. 
The tragus. 6. The lobe of the ex- 
ternal ear. 7. Points to the scapha, 
and is on the front and top of the 
pinna. 8. The concha. 9. The mea- 
tus auditorius externus. 



122 



DISSECTIO^^ OF THE HEAD AXD NECK. 



Fig. 39. 



The Arteries of the auricle are derived from the poste- 
rior auricular, and the auricular branches of the temporal. 
Quite a large iDranch from the posterior auricular enters the 
concha between the anti-helix and the processus caudatus. 

The I^ERYES come from several sources ; as the auricula- 
ris magnus, the facial, the fifth, and the pneumogastric. The 
concha is supplied by a branch which jDerforates the cartilage 
just above the anti-tragus. 

The meatus auditoriiis externus^ Fig. 41 (s), is about an inch 
in leng-th. The inner half of it is osseous, and belongs to the 
temporal bone. It is slightly curved, with its convexity 
upwards. Its lower wall is longer than the upper, on account 
of the oblique position of the membrana tympani. A trans- 
verse vertical section of it presents 
a figure somewhat oval or ellipti- 
cal, the vertical diameter being the 
longest. The middle of it is not 
quite so large as the extremities. 
The outer portion is partly fibrous 
and partly cartilaginous. The 
fibrous structure forms about the 
upper fourth of the canal. There 
are two or three fissures in the 
cartilaginous portion called the 
fissures of Saniorini. The struc- 
ture of this part of the canal 
admits of some mobility. 

The meatus is lined by a reflec- 
tion of the skin from the auricle. 
It is very thin and delicate, and 
covered with fine hairs. In old 
persons there are usually some 
quite long stiff hairs near the ex- 
ternal orifice, which seem to afford 
some protection against the en- 
trance of foreign bodies. In the 
structure of the lining membrane 
are a number of sebaceous follicles called the ceruminous 
glands. They are of a yellowish color when cut, and secrete 
an unctuous substance resembling wax. This sometimes ac- 
cumulates and becomes hard, causing deafness. The meatus 
should be observed with care by the student. It may be 




Represents the Cartilage of 
THE External Ear with some of 
ITS MrscLES.— 1/2. The helieis 
major muscle on the front of the 
helix. 3, 4. The helieis minor mus- 
cle. 5, 6. The tragicus muscle on 
the front surface of the tragus. 7, 
8. The anti-tragicus muscle. 



MIDDLE EAR, OR TYMPANUM. 123 

examined by allowing tlie rays of light to enter in a direction 
to fall on the membrana tympani, and to expose the whole of 
the interior surface of the meatus. 



The tympanum is a small circular cavity, situated between 
the meatus and the labyrinth, or internal ear. It resembles 
somewhat a section of the meatus, or it may be regarded as 
a prolongation of that tube into the base of the petrous por- 
tion of the temporal bone, to the extent of about one- fourth 
of an inch. It is cut off from the meatus by a membrane, 
which forms its external wall, while the septum between it 
and the internal ear forms its internal wall. This cavity is 
about half an inch in diameter, which is rather greater than 
that of the meatus. 

In studying it, three surfaces are presented ; its external 
and internal walls, and its circumference. 



Fig. 40. 





Membrana Tympani from the outer (a) and from the inner (b) sides. — 1. 
membrana tympani. 2. Malleus. 3. Stapes. 4. Incus. 

Its external wall is formed by the membrana tympani, and 
the inner margin of the parietes of the meatus. The mem- 
brana tympani, Fig. 40, A, B, is inclined inwards in a direction 
from above downwards, thus increasing the length of the floor 
of the meatus. It is concave externally, with its correspond- 
ing convexity projecting into the tympanum. It has attached 
to the upper part of its inner surface the handle of the malleus. 
It is composed of three lamina"). The outer one is reflected 
from the parietes of the meatus, and the inner one froni the 
walls of the tympanum ; the middle one is fibrous, and is fixed 
to a groove in the circumference of the tympanic orifice of the 



124 DISSECTION OF THE HEAD AND NECK. 

meatus. In the foetus it is attaclied to an osseous ring, wMcli 
is distinct from the rest of the petrous bone. It contains 
some small vessels. The following points are to be noticed 
on the inner wall: — 

Th.Q fenestra ovalis^ Fig. 41 (lo), is situated in the upper 
part, directly opposite the roof of the meatus. Its long 
diameter is inclined do^vnwards and forwards. The upper 
border of it is arched, while the lower is nearly straight. It 
is occupied in the recent subject by the stapes and by a mem- 
brane. The fenestra rotunda is located in the posterior part 
of the inner wall, and lower down than the fenestra ovalis. 
It is situated at the bottom of quite a deep fossa. Between 
and below these two orifices is seen the promontory. Several 
small grooves are sometimes observed on the promontory for 
the lodgment of filaments of Jacobson's nerve; instead of 
grooves, they may exist in the form of canals in the bone. 
Just in front of, and a little below the anterior extremity of 
the fenestra ovalis, is the tympanic orifice of the canal for the 
tensor tympani muscle. The processus cochleariformis is a 
projection of the wall of this canal into the tympanum. The 
aqueduct of Fallopius forms a curved ridge just above the 
fenestra ovalis. Behind the fenestra ovalis, and near the 
posterior wall, is the p>yrainid^ with a small opening upon its 
apex which is occupied by the stapedius muscle. The carwbl 
for the transmission of Jacobson's branch of the glosso- 
pharyngeal nerve enters the tympanum at the lower part of 
the promontory. 

In the posterior part of the tympanum is a large opening 
which leads into the mastoid cells. These cells are lined by 
mucous membrane, and contain air during life. They are 
analogous to the frontal and sphenoidal sinuses. Below the 
mastoid opening is a small foramen, through which passes 
the chorda tympani nerve, after it leaves the portio dura. 

There is nothing in the floor of the tympanum which 
deserves particular notice. It is quite thin, and is formed 
by a prolongation inwards of the floor of the meatus. It 
corresponds to the parotid fossa externally. 

In the anterior part of the tympanum is the fissure of 
GlaseriuSj and the small foramen through which the chorda 
tympani makes its exit. There is also a small opening for 
the superficial petrosal branch of Jacobson from the otic 
ganglion. The tympanic orifice of the Eustachian tube, 
Fig. 41 (i 3), occupies the greater part of the anterior wall of 



MIDDLE EAK, OR TYMPANUM. 



125 



the tympanum. The osseous portion of this tube is separated 
from the canal for the tensor tjmpani muscle by the septum 

Fig. 41. N 




A DiAGEAM OF THE Eae. — p. The pinna. (. The tympanum. I. The laby- 
rinth. 1. The upper part of the helix. 2. The anti-helix. 3. The tragus. 4. 
The anti-tragus. 5. The lobulus, 6. The concha. 7. The upper part of the fossa 
innominata. 8. The meatus. 9. The membrana tympani, divided by the section. 
10. The three little bones, crossing the area of the tympanum, malleus, incus, and 
stapes ; the foot of the stapes blocks up the fenestra ovalis upon the inner wall of 
the tympanum. 11. The promontory. 12. The fenestra rotunda ; the dark open- 
ing above the ossicula leads into the mastoid cells. 13. The Eustachian tube; the 
little canal upon this tube contains the tensor tympani muscle in its passage to the 
tympanum. 14. The vestibule. 15. The three semicircular canals — horizontal, 
perpendicular, and oblique. 16. The ampullae upon the perpendicular and hori- 
zontal canals. 17. The cochlea. 18. A depression between the convexities of the 
two tubuli which communicate with the tympanum and vestibule : the one is the 
scala tympani, terminating at 12, the other is the scala vestibuli. 

cochleariforme. This part of the tube is small in the pre- 
pared bone, and much smaller in the recent bone before its 
membranous lining is removed. 

In the upper wall is a depression which is occupied by 
the head of the malleus and the short leg of the incus. This 
wall is perforated by several foramina, for the transmission 
of vessels to the dura mater. 

The ossicula auditus, or small bones of the ear, Fig. 42, 
are the malleus, incus, orbiculare, and stapes. 

11* 



126 



DISSECTION OF THE HEAD AND NECK. 



Fig. 42. 



These form a cliain, extending across the tympanum from 
the membrana tympani to the fenestra ovaL's. 

The MALLEUS is situated next to the membrana tympani. 
It consists of a head, neck, handle, and two processes, long 
and short. The head is round and smooth above, and con- 
cave below, for articulating with the incus. From the neck^ 
which is flattened, the two processes arise ; the short one is 
directed to the upper part of the membrana tympani, against 
which it rests; the long one, called the processus gracilis^ 
arises from the anterior part of the neck, and projects for- 
wards towards the Glaserian fissure. The laxator tympani 
muscle is inserted into it. The handle^ or manubrium^ has 
nearly a vertical position, and adheres closely to the fibrous 
layer of the membrana tympani, the radiating fibres of which 

diverge from it. It extends to 
the centre of the membrane, and 
curves slightly outwards. 

The INCUS is placed on the inner 
side of the preceding. It presents 
a body and two processes. There 
is a concavity on the body for the 
reception of the head of the mal- 
leus. The short process is of a 
conical shape, and directed back- 
wards to the opening into the 
mastoid cells. Its extremity is 
attached by a ligament. The long 
process descends a little behind, 
and nearly parallel to the handle 
of the malleus, and a short dis- 
tance from it. Its lower end is 
curved inwards. 

The OEBICULAKE is very fre- 
quently fixed to the extremity of 
the long process of the incus. It 
is round, and flattened like a disk. 
The STAPES presents a head, two 
crura, and a base. Its position is 
horizontal. The head articulates 
with the orbiculare, and the hase fits into the fenestra ovalis. 
The posterior cms is longer and more curved than the anterior. 




Ossicles of the Left Ear 
articulated, and seen from 

the outside and below. m. 

Head of the malleus, below which 
is the constriction, or neck. g. 
Processus gracilis, or long process, 
at the root of which is the short 
process. Ti. Manubrium, or han- 
dle, fic. Short crus; and ^c, long 
crus of the incus. The body of 
this bone is seen articulating with 
the malleus and its long crus, 
through the medium of the orbi- 
culare o, here partly concealed, 
with the stapes, s. Base of the 
stapes. Magnified three diame- 
ters. 



OR LABYRINTH. 127 

These bones are connected to each other by capsular liga- 
ments, which contain synovial membranes. They are also 
connected to the parietes of the tympanum by three liga- 
ments. The head of the malleus is attached to the roof by 
a ligament ; the short process of the incus is connected to 
the opening into the mastoid cells, and the base of the stapes 
to the margin of the fenestra ovalis, by ligamentous fibres. 

The muscles of the tympanum are the tensor tympani, the 
laxator tympani, and the stapedius. 

The TENSOR TYMPANI, Fig. 45, a, arises from the cartilage 
of the Eustachian tube and the contiguous portion of the 
sphenoid bone, and also from the bony canal which it occu- 
pies just above the septum cochleariforme. It enters the 
anterior part of the tympanum, and is reflected outwards, to 
be inserted into the handle of the malleus immediately below 
the processus gracilis. 

The LAXATOR TYMPANI is regarded very generally as liga- 
mentous, and not muscular in its structure. It is attached to 
the point of the processus gracilis, and passes through the 
Glaserian fissure to become connected with the internal lateral 
ligament of the temporo-maxillary articulation. 

Another laxator has been described extending from the 
upper part of the membrana tympani to the malleus. 

The STAPEDIUS arises from a depression on the pyramid, 
and passes downwards and forwards to be inserted into the 
neck of the stapes. 

The tympanum is lined by a very thin delicate mucous 
membrane. This adheres closely to the periosteum beneath 
it. It invests the small bones, and covers the vessels and 
nerves ; is reflected into the mastoid cells, but not into the 
labyrinth ; closes the fenestra rotunda, and the space between 
the crura of the stapes. 



OR LAliYRINTII. 

The internal ear contains the peripheral expansion of the 
nerve of hearing. It lies deep in the petrous portion of the 
temporal bone, and consists of several compartments. From 
its complex character it has been called the labyrinth. Its 
compartments are the vestibule, the semicircular canals, throe 
in number, and the cochlea. I^hc vestibule is situated in 



128 DISSECTION OF THE HEAD AND NECK. 

the centre, with the cochlea in front and the semicircular 
canals behind. These osseous cavities contain within them 
membranous sacs, which constitute the membranous laby- 
rinth. A fluid fills the sacs, and also the osseous cavities 
outside of the sacs. 

The Yestibule, Fig. 41 (i 4), is placed between the fenestra 
ovalis on the external side, and the macula crihrosa at the 
bottom of the meatus auditorius internus on the inside. The 
distance between these two walls is about an eighth of an 
inch. Its antero-posterior diameter is about one-fifth of an 
inch. It presents in its circumference three enlargements, 
called cornua^ a superior, an anterior inferior, and a posterior 
inferior. The semicircular canals open by three orifices into 
the posterior inferior cornu, and by two into the superior, while 
the vestibular scala opens into the anterior inferior cornu. 
Thus, it will be seen, that the parietes of the vestibule are 
perforated by six openings of considerable size. Besides 
these, there are also small foramina for the transmission of 
filaments of the auditory nerve, and the aqueduct of the ves- 
tibule opening into its posterior part. The vestibule presents 
two depressions, an inferior, called \h.Q fovea hemispherica, and 
a superior, called \hQ fovea elliptica; these are separated by a 
crest named eminentia pyramidalis. 

The Semicircular Canals, Fig. 41 (is), form each about 
three-fourths of a circle. They are not exactly round tubes, 
but compressed slightly on the sides. Two of them open into 
the vestibule by a common orifice. Dilatations occur at three 
of their orifices; they are called ampulloe. These osseous 
canals are distinguished from each other by their db^ection 
and position. Thus, there is a superior vertical, posterior 
vertical, and a horizontal one. The superior vertical has its 
convexity upwards; its situation is indicated by a promi- 
nence on the petrous bone, which is very distinct in the foetus ; 
its direction is transversely across the bone. The posterior 
vertical has a direction parallel to the axis of the petrous 
bone ; its convexity looks upwards and outwards. The h(yri- 
zontal canal is convex outwards. It is shorter than the other 
two. The common orifice is formed by the two vertical canals. 

The Cochlea, Fig. 41 (1 7), resembles in shape the shell of 
a snail. Its base is situated at the bottom of the meatus audi- 
torius internus, while its apex is directed forwards, outwards, 



INTERNAL EAR, OR LABYRINTH. 



129 



and downwards. It seems to consist of a tube tapering from 
one end to the other, and coiled two and a half times roimd 

Fig. 43. 




A HIGHLY MAGNIFIED VIEW OF THE EXTEENAL EACE OP THE BONY LABYRINTH OF 

THE Left Side, OPENED so as to expose the Vestibule and its contents, <&c. — The 
difl'erence of color in the shades of this figure is intended to assist in distinguishing 
the external from the internal faces of the labyrinth, and also the cavities supposed 
to be occupied by the liquor of Cotunnius. 1. The ampulla of the superior semi- 
circular canal. 2. The ampulla of the external canal. 3. The ampulla of the 
inferior canal. 4. The superior membranous semicircular canal. 6. External 
membranous canal. 6. The inferior membranous canal. 7. The spaces between 
the bony and membranous semicircular canals, thought to be occupied by the liquor 
Cutunnii. 8. The common tube formed by the union of the superior and inferior 
membranous canals. 9. The place where the external semicircular canal opens into 
the sacculus ellipticus of the vestibule. 10. The sacculus ellipticus containing the 
otoconia of Breschet, seen at 11. 12. Sacculus sphericus, containing also some 
otoconia, as seen at 13. 14, 15, 16, 17, 18. The expansions of the auditory nerve to 
the membranous canals and the sacculus ellipticus, and also to the sphericus. 19. 
The turns of the lamina spiralis. 20. The scala tympani. 21. The nervous ex- 
pansion to the posterior ampulla. 22. The scala vestibuli. 23. The modiolus. 



a central column. A partition, Fig. 43 (i 9), passes from the 
base to the apex in this tube, dividing it into two compart- 
ments, called scalce. One of these scah\}. opens into the tym- 
panum, and tlie other into the vestibule, lieucc they are 
named the iymj.)anic and the veslilndar scala>. 



180 DISSECTION OF THE HEAD AND NECK. 

The septum between the scalse is called the laraina spiro2is ; 
this is partly osseous and partly membranous; it is spoken of 
as the lamina spiralis membranacea^ and the lamina spiralis 
ossea. The osseous portion is attached by its inner border 
to the central column, or 'modiolus^ and in the dried prepara- 
tion looks like the thread of a screw. The upper extremity 
of this projects slightly from the central column, and forms 
the hamulus. Both it and the outer or membranous portion 
consist of two lamellae, between which are placed filaments 
of the auditory nerve. The osseous lamina is broadest at 
the base of the cochlea, while the membranous is broadest 
at the apex. The modiolus is a column of a conical shape, 
with its base perforated by many small foramina, and traversed 
by several osseou.s canals for the transmission of the filaments 
from the internal meatus, which pass through the interior of 
this tube to get in between the lamellge of the lamina spiralis. 
Its apex is somewhat expanded, to which portion of it the term 
infundihulum is applied ; this again is covered over by what 
is called the cupola. The modiolus is not a distinct structure, 
but blended with the inner wall of the tube of the cochlea, 
and the inner border of the lamina spiralis. The helicotrema 
is a small opening between the scalse ; it is situated immedi- 
ately beneath the hamulus. This is the only communication 
between these semicylindrical tubes. The aqueduct of the 
cochlea opens into the scala tympani near the fenestra ovalis. 

The different cavities are lined by a very delicate fibro- 
serous membrane. The fibrous layer adheres closely to the 
bone, and answers the purpose of a periosteum ; the serous 
layer secretes \hQ perilymph^ or liquor Gotunnii. This lining 
membrane assists in closing the fenestra rotunda and the 
fenestra ovalis ; it also forms the lamina spiralis membranosa. 

The Membkanous Labyeinth is found only in the vestibule 
and semicircular canals. The vestibular portion consists of 
the utriculus^ or common sinus, and the sacculus. It is not 
certainly ascertained whether these two membranous cavities 
communicate with each other or not. The utriculus occupies 
the posterior part of the vestibule, and the sacculus the ante- 
rior and inferior parts. The membranous semicircular canals 
correspond with the osseous canals in number, in ampullae, 
and in their openings into the utricle. The membranous 
labyrinth is filled with a semi-fluid called the endolymph. 



131 

There are observed attached to the utricle and saccule 
small calcareous bodies, called otolithes, or otoconia. 

The arteries of the tympanum enter it in the following 
manner : A small branch from the middle meningeal passes 
through the hiatus Fallopii; another from the internal max- 
illary enters it through the Griaserian fissure; a third one 
comes from the stylo-mastoid, and gets in at the lower end of 
the aqueduct of Fallopius; it receives branches through the 
Eustachian tube from the ascending pharyngeal or inferior 
palatine arteries ; the internal carotid also sends a twig into 
it through a small foramen from the carotid canal. 

The artery to supply the labyrinth passes through the 
meatus auditorius internus. It sometimes comes from the 
superior cerebellar, and sometimes from the basilar. At the 
bottom of the meatus it divides into a vestibular and a coch- 
lear branch. 

The nerves connected with the middle and internal ear are 
derived from several sources. There are four which enter 
the petrous bone; one of these terminates in the labyrinth; 
the other three pass through the bone, traversing in their 
course the tympanum. The portio dura and portio mollis 
enter it through the meatus auditorius internus ; the former 
leaves it through the foramen stylo-mastoideum ; the latter is 
distributed to the labyrinth. The vidian enters through the 
hiatus Fallopii, and makes its exit as the chorda tympani, 
through a small aperture near the Griaserian fissure. Jacob- 
son's branch of the glosso-pharyngeal passes through a small 
foramen situated between the jugular fossa and carotid fora- 
men, and leaves the bone as the superficial petrosal branch of 
Jacobson, just below the hiatus Fallopii to go to the otic 
ganglion. 

The PoETio Mollis, Fig. 44 (i 5, 1 e, 1 7), at the bottom of 
the meatus divides into two branches, one for the cochlea and 
one for the vestibule and semicircular canals. The anterior or 
cochlear division passes through by a number of filaments the 
perforated base of the modiolus, and thus enters its osseous 
canals, from which the filaments enter nearly at right angles 
the space between the lamella) of the lamina spiralis, to 
terminate in a delicate nervous membrane in the form of 
papillae. 

l^\iQ posterior or vestibular division separates into three lasci- 



132 DISSECTION OF THE HEAD AND NECK. 

culi ; tlie superior of which, enters the vestibule to expand on 
the utricle and on the ampullae of the superior vertical and 

Fig. 44. 




A ViKW OF THE Labyrinth in an inverted position, laid open so as to show 
THE distribution OP THE NERVES. — 1, 2, 3. The cochlea laid open in its fullest ex- 
tent, so as to show the lamina spiralis. The figures are placed on the two turns and 
and a half. 4, 5, 6. The remains of the parietes of the cochlea. 7, 8. The vestibule. 
9, 10. Superior canal. 11, 12. Inferior canal. 13. The external canal. 14. The 
semicircular membranous canals. 15, 16, 17. The auditory nerve in its course to 
the labyrinth. 

horizontal membranous semicircular canals; the middle passes 
through the macula cribrosa to expand on the saccule ; the 
inferior enters the posterior part of the vestibule to go to the 
ampulla of the posterior vertical membranous canaL 

The PoETio Dura leaves the meatus and enters the aque- 
duct of Fallopius, passes forwards and outwards to communi- 
cate with the hiatus Fallopii, where it is joined by the vidian 
nerve, and presents a ganglionic enlargement ; it then passes 
backwards and downwards over the fenestra ovalis to reach 
the foramen stjlo-mastoideum. In its course through the 
tympanum it passes from the upper and anterior part of the 
inner wall to the lower and inner part of the posterior wall. 
It is connected by one or two filaments to the portio mollis. 

The Vidian, after passing through the hiatus Fallopii, 
joins the portio dura and accompanies it through the tym- 
panum and a short distance into the stylo-mastoid canal, 



INTEENAL EAR, OR LABYRINTH. 



133 



then leaves it, returns by a bony canal into tlie tympanum, 
and goes forwards between the handle of the malleus and 
long process of the incus, to a small foramen close by the 
Glaserian fissure. After leaving the portio dura, it is called 
the chorda tympani. 

The Nerve of Jacobson, from the giosso-pharyngeal, 
enters the tympanum just below the promontory, and after 
giving off the following branches leaves it through an osseous 
canal in the upper and anterior part near the hiatus Fallopii : 

Fig. 45. 




a Drawing of the Tympanic Nerve from Bresciiet's work on the ear. — a. 
Squamous part of temporal bone. B, B. Petrous portion of same. c. Lower maxillary 
nerve, d. Internal carotid arterj'. a. Tensor tympani muscle. 1. Carotid plexus. 
2. Otic ganglion. 3. Giosso-pharyngeal nerve. 4. Tympanic ncrvo. 5. Branches 
to carotid plexus. 6, Branch to fenestra rotunda. 7. Branch to fenestra ovalis. 8. 
Branch to join the large superficial petrosal nerve. 9. Small superfieii>l petrosal 
nerve. 10. Nerve to tensor tympani muscle. 11. Facial nerve. 12. Chorda tym- 
pani. 13. Petrous ganglion of the giosso-pharyngeal. l-i. Branch to the membrane 
lining the Eustachian tube. 

One branch enters the carotid canal to join the sympathetic; 
another joins the vidian in the hiatus FaUopii ; a third goes 
to the Eustachian tube; a fourth to the fenestra ovalis, and a 
fifth to the fenestra rotunda. By a division of this nerve into 
12 



134 DISSECTION OF THE HEAD AND NECK. 

filaments, and these filaments reuniting, the tympanic plexus 
is formed. Before entering the tympanum, Jacobson's nerve 
is connected by filaments with the pneumogastric and facial 
nerves. This nerve joins the superficial petrosal branch of 
Jacobson, and thus forms a communication between the gan- 
glion of the glosso-pharyngeal and the otic ganglion. 



Sect. X. — Dissection of the Nose. 

The nose is the organ of smell ; it affords to the lungs an 
external communication which is constantly open for the 
transmission of air ; it furnishes a passage or common outlet 
to several cavities lined by mucous membrane ; it also con- 
tributes essentially to the perfection of the voice. It occu- 
pies a central position in the facial portion of the head. It 
has on each side of it the orbit above and the antrum High- 
mori below, and extends from the floor of the cranial cavity 
above to the roof of the mou.th below. It opens anteriorly 
upon the face, and posteriorly into the upper part of the 
pharynx. It is divided into two compartments called the nasal 
fossae, which are separated by an osseo -cartilaginous septum. 

The term nose is more commonly applied to that portion 
which projects upon the face. The structure of the lower 
and most prominent portion of this is cartilaginous, while 
the upper part is osseous. The muscles, vessels, and nerves 
of the nose have already been described. 

The bones are the nasal and the nasal processes of the su- 
perior maxilla. 

The cartilages^ or fihro-cartilages^ form the framework of 
the movable part of the nose. They furnish a structure of 
sufficient firmness to preserve the anterior nares patent, while 
their mobility is a protection against injury, and allows the 
nostrils to be closed or expanded. 

These cartilages consist of the septal or middle^ and two 
lateral upon each side, a superior and inferior^ or alar. 

The middle cartilage. Fig. 46 (4), forms the anterior septum 
of the nasal fossae. The columna is the septum between the 
anterior nares. This cartilage is of an irregular triangular 
shape ; its centre is not so thick as the margins, and is fre- 
quently inclined to one side or the other. Its upper and 
posterior border is attached to the vertical lamella of the 



OF THE NOSE. 



135 



Fig. 46. 



etlimoid, and its posterior inferior border is received between 
the edges of ttie vomer and the palatine 
processes of the superior maxillge ; its 
anterior border is connected to the nasal 
suture and to the two inferior lateral 
cartilages. It sometimes projects back- 
wards between the ethmoidal lamella and 
the vomer to the rostrum of the sphenoid 
bone. 

The superior lateral cartilage^ Fig. 47 (i), 
on each side is attached above to the 
lower border of the nasal bone, poste- 
riorly to the nasal process of the superior 
maxilla, below to the inferior lateral car- 
tilage of the same side, and in the median 
line to the septal cartilage ; the two car- 
tilages are not directly attached to each 
other at their anterior margins. The 
anterior margin is thicker than the pos- 
terior. They are of a triangular shape. The inferior lateral or 




View of the Carti- 
lages OF THE Nose, 

LOOKING INTO THE NOS- 
TRILS FROM BELOW. — 2. 

Outer part of the lower 
lateral cartilages. 2'. 
Inner part of the same. 
4. Lower edge of the 
cartilage of the septum. 



Fig. 47. 



Fig. 48. 





View of the Bones and Carti- 
lages OF THE OUTER N OSE, FROM THE 

KiGHT Side. — a. Nasal bono. 6. Nasal 
process of upper maxillary bone. 1. 
Right upper lateral cartilage. 2. Lower 
lateral cartilage, its outer part. 2*. 
Inner part of the same. 3. Sesamoid 
cartilages. 



Front View of the Cartilages op 
THE Nose. Above is seen the Out- 
liiNE OF the Nasal Bones. — a. Front 
edge of the septal cartilago. h, h. 
Lateral cartilages, c, c. Alar carti- 
lages, with their appendages. 



136 



DISSECTION OF THE HEAD AND NECK. 



alar cartilages^ Fig. 48, c, c, nearly snrroTind tlie anterior nares; 
the outer and posterior part of each is narrow, but is en- 
larged anteriorly to form with its fellow on the opposite side 
the apex of the nose. Each projects backwards below the 
septal cartilage to assist in forming the columna. Behind 
where their outer portions are attached by dense fibrous 
tissue to the maxilla, are usually on each side two or three 
small cartilages, called the sesamoid cartilages. The inner 
portion of each alar cartilage is connected behind to the nasal 
spine. The lower parts of the alse of the nose are formed by 
dense areolar tissue. 

The ISTasal Foss^ should be studied in the first place in 
a prepared skull, which has been divided by a vertical sec- 
tion made a little to one side of the median line, so as to 
leave the osseous septum entire. A knowledge of the nasal 
fossae is too important to be neglected by the student. If he 
be familiar with the osseous walls of these cavities, he will 
encounter very little difficulty in dissecting and understand- 
ing the soft parts connected with them. 

Each nasal fossa is somewhat wedge-shaped ; the thin edge 
looks upwards, and is rounded off anteriorly and posteriorly, 
to correspond to the arched roof of this cavity. 

The inner wall, Fig. 49, is formed above by the vertical 

Fig. 49. 




Osseous and Cartilaginous SEPxm of tee Nose, seen from the Left 
Side. — a. Nasal bone. h. Superior maxillary bone. c. Sphenoidal sinus, d. 
Central or perpendicular plate of the ethmoid bone. e. Vomer. 2*. Inner part 
of the (right) lower lateral cartilage of the nose. 4. Cartilage of the septum. 



OF THE NOSE. 



137 



lamella of the ethmoid bone ; below and behind hj the 
vomer ; the angular space between these bones anteriorly 
is occupied by the septal cartilage. The outer wall, Fig. 50, 
is very uneven on account of the projection of the turbinated 
bones into the fossa. 

The IKFERIOR TURBINATED BONE, Fig. 50 (7), is a separate 
piece. Its inferior free border is situated about half-way be- 
tween the superior maxilla and the septum nasi, and about four 
lines from the floor of the fossa. The distance between its 
central part, which is more prominent than the extremities, 
and the septum, is usually less than a fourth of an inch. 
The space below and between this bone and the nasal wall 



Fig. 50. 




The Outer Wall of the Left Nasal Fossa covered avith the Pituitary 
Membrane. — 1. Frontal bone. 2. Na,sul bone. 3. Superior maxillary. 4. Sphe- 
noid. 5, The upper spongy bone. 6. Middle spongy bone. 7. Lower spongy 
bone. The three meatuses of the nose are seen below the three last-named bones 
respectively. 8. The opening of the Eustachian tube. 

of the antrum is the inferior 7neatus ; the ductus ad nasum 
opens into the anterior extremity of this meatus. The sur- 
face of the inferior turbinated bono is very rough, presenting 
numerous elevations and depressions. Its attachments are 
slight, consequently it is easily broken awa}'. 



138 DISSECTION OF THE HEAD AND NECK. 

The MIDDLE TUKBINATED BONE, Fig. 50 (e), is a part of tlie 
etliinoid; and is not half as large as the inferior. This is situated 
in the lower part of the upper half of the nasal fossa ; its free 
border is separated from the inferior about two lines. The 
middle meatus is the space below and on the outside of it. 
The antrum. Highmori, the anterior cells of the ethmoid and 
the frontal sinus open into this meatus. The frontal sinus 
is nearly half an inch above and in front of its anterior ex- 
tremity, and the opening between them is called the infundih- 
ulum. 

The SUPERIOE TURBINATED BONE, Fig. 50 (s), is about half 
an inch in length ; it is separated from the posterior part of 
the middle turbinated bone by the superior meatus^ which is a 
small sulcus, forming a sort of common opening to the pos- 
terior cells of the ethmoid. The spheno-palatine foramen is 
situated just behind this meatus, and the opening from the 
sphenoidal sinus just behind and above it. Thus it will be 
seen that the frontal and sphenoidal sinuses, the antrum of 
the maxilla, the cells of the ethmoid bone and the nasal duct 
all communicate with the nasal fossa. 

A very small portion of the lachrymal bone is seen in the 
anterior extremity of the middle meatus. This should be 
noticed, as showing the relation of the lachrymal sac to the 
nasal fossa. The vertical lamella of the palatine bone forms 
a portion of the outer wall posteriorly. 

The ROOF of each of the nasal fossae is arched in its antero- 
posterior direction. It is formed, proceeding from before 
backwards, by the nasal bones, the floor of the frontal sinus, 
the cribriform plate of the ethmoid, and the anterior wall of 
the sphenoidal sinus. The central or horizontal portion is 
perforated for the olfactory nerve and the internal nasal branch 
of the ophthalmic ; the anterior sloping portion has a groove 
for the nasal branch just mentioned ; the posterior portion, 
which is nearly vertical, contains the opening from the sphe- 
noidal sinus. The form of the roof may be modified some- 
what, according to the development of the frontal and sphe- 
noidal sinuses. 

The FLOOR of each fossa is nearly horizontal in the antero- 
posterior direction, and concave transversely ; it is narrowest 
at its anterior extremity. The central part is formed by the 
horizontal plate or palatine process of the superior maxilla; 
anteriorly, by the bony substance just above the alveolar pro- 



OF THE NOSE, 



139 



cess which contains the canine teeth ; and behind, by the hori- 
zontal plate of the palatine bone. About a fourth of an inch 

Fig. 51. 




A Vertical Section of the Middle Pabt of the Nasal Foss^, giving a pos- 
terior VIEW OF the arrangement of the Ethmoidal Cells, &c. — 1 . Anterior 
fossa of the cranium. 2. The same covered b^ the dura mater. 3. The dura mater 
turned up. 4. The crista galli of the ethmoid bone. 5. Its cribriform plate. 6. 
Its nasal lamella. 7, 7. The middle spongy bones. 8. The ethmoidal cells. 9. The 
OS planum. 10. Inferior spongy bone. 11. The vomer. 12. Superior maxillary 
bone. 13. Its union with the ethmoid. 14. Anterior parietes of the antrum High- 
morianum, covered by its membrane. 35. Its fibrous layer. 16. Its mucous mem- 
brane. 17. Palatine process of the superior maxillary bone. 18. Roof of the 
mouth covered by the mucous membrane. 19. Section of this membrane. A 
bristle is seen in the orifice of the antrum Highmorianum. 



behind the nasal spine, and close to the septum nasi, is situ- 
ated the foramen incisivum, or anterior palatine foramen. 

The relation of the external orifice of the Eustachian tube, 
Fig. 50 (s), to the nasal cavity, should be noticed in the pre- 
pared skull, but more particularly in the recent subject, with 
reference to the introduction of an instrument into it through 
the nasal fossa. 

To examine the nasal fossa) in the recent subject, the head 
mu.st be divided vertically, as was mentioned in connection 
with the prepared cranium. A fine saw Avithout any back is 
best for this purpose. 

The nasal fossil are lined by a omicoits menihraue, which is 
continued into the sphenoidal, frontal, and maxillary sinuses, 
and ethmoidal cells; it is continuous through the lachrymal 
passages with the conjunctiva; Avith the nmcous membrane of 
the pharynx and Eustachian tubes tlirough the posterior nares, 



140 DISSECTION OF THE HEAD AND NECK. 

and with, the skin through the anterior nares. On the septum 
and turbinated bones it is soft, thick, and very vascular ; in 
other places it is blended with the periosteum, and might be 
called a fibro-mucous membrane. At the lower borders of 
the turbinated bones it forms quite thick folds ; and at the 
inferior orifice of the nasal duct it forms a fold which has 
been spoken of as a valve. The spheno-palatine, ethmoidal, 
and anterior palatine foramina are covered over and con- 
cealed bj it in the fresh preparation. The openings into the 
different sinuses are considerably diminished in size by it, 
and the periosteum beneath it. It has a columnar epithelium. 
In the sinuses, the mucous membrane is thinner, less vascu- 
lar, and covered by the squamous epithelium. Cilia exist 
upon its surface, both in the sinuses and nasal fossae. 

The following nerves are found in the nasal fossa. As there 
are no muscles to be supplied in this cavity, no motor nerves 
are required. 

The Olfactoky, Fig. 52 (5), enters it from above by nume- 
rous filaments, which descend about an inch on the septum, and 
to the middle meatus on the outer wall. The filaments form 
minute plexuses beneath the mucous membrane. The exact 
manner in which they terminate is not known. By tearing 
off the mucous membrane, the filaments of the olfactory may 
be traced to their termination in this structure. It will be 
seen from the distribution of this nerve, that air loaded with 
odorous particles must reach the upper part of the nasal ca- 
vity in order to make an impression on the peripheral expan- 
sion of the nerve of smell. The olfactory nerve is spread out 
upon only a very small portion of the entire surface of the 
nasal fossa. 

The Spheno-Palatine Nerve, Fig. 52 (e), consisting usu- 
ally of several branches, enters the nasal fossa just behind 
the superior meatus, through the spheno-palatine foramen. 
Several small branches, called the external, are distributed to 
the mucous membrane on the outer wall of the fossa, some 
filaments reaching the septum ; a much larger branch, called 
the internal or naso-palatme, crosses over to the septum, and 
descends first vertically, and then horizontally, to reach the 
anterior palatine foramen, or foramen incisivum, in which -it 
is said to connect with the ganglion of Chg^uet, Fig. 52 (9) ; it 



OF THE NOSE. 



141 



then passes through this foramen to the mucous membrane 
of the hard palate, ju.st behind the incisor teeth. 

Fig. 52. 




A View op the First Pair or Olfactory Nerves, with the Nasal Branches 
OF the Fifth Pair. — 1. Frontal sinus. 2. Sphenoidal sinus. 3. Hard palate. 4. 
Bulb of the olfactory nerve. 5. Branches of the olfactory nerve on the superior 
and middle turbinated bones. 6. Spheno-palatine nerves from the second branch 
of the fifth pair. 7. Internal nasal nerve from the first branch of the fifth. 8. 
Branches of 7 to the Schneiderian membrane. 9. Ganglion of Cloquet in the fora- 
men incisivum. 10. Anastomosis of the branches of the fifth pair on the inferior 
turbinated bone. 

These nerves ramifj between the mucous membrane and 
periosteum. To obtain a distinct view of them, the part 
should be kept for some time in dilute nitric acid ; when, by- 
separating the membrane from the bone, they can be seen 
from the fibrous surface. 

The anterior palatine nerve gives off a branch which enters 
the nasal fossa near the posterior extremity of the inferior 
turbinated bone, and ramifies in the lower part of the fossa. 

The internal nasal branch, Fig. 52 (7), of the ophthalmic, 
enters the nasal cavity through the anterior part of the eth- 
moid, near the crista galli, sends some twigs to the septum 
and outer wall, and then passes down on the inner surface of 
the nasal bone to its junction with the lateral cartilages of the 
nose, where it perforates the fibrous structure connecting the 
cartilage and bone, and is distributed to the integument cover- 
ing the nose. In its course, some filaments penetrate the bone. 

The arteries entering the nasal fossa consist of branches 
from the splieno-pahitiiie, the infra-orbital, the palatine, the 



142 DISSECTION OF THE HEAD AND NECK. 

pterygo-palatine, tlie snpra-orbital, tlie etlimoidal, and tlie 
facial. From these various sources tlie mucous membrane of 
the nasal fossa is abundantly supplied with arterial blood. 

The veins^ Fig. 8, h^ correspond with the arteries. Some 
branches find their way into the frontal sinus, and through 
the foramen caecum communicate with the superior longitudi- 
nal sinus of the dura mater. 

The student should study the nasal fossae with reference to 
plugging the nares to arrest hemorrhage; the removal of 
polypi, and foreign bodies which may happen to be lodged in 
them; the introduction of instruments to reach the Eustachian 
tube, or to be conducted into the pharynx through the nasal 
cavity ; their proximity to the brain and its meninges ; and 
their connection with the sphenoidal, frontal, and maxillary 
sinuses, Fig, 52 (i, 2), and the ductus ad nasum. The exact 
relation of the osseous sinuses, just mentioned, to the nasal 
fossae should be carefully noted; the manner in which a puru- 
lent collection in either of these sinuses would be affected, in 
regard to its escape, by the position of the head. 

If, for instance, pus should be formed in the maxillary 
sinus or antrum, a large proportion of it would necessarily 
be retained as long as the head was kept in a vertical posi- 
tion, on account of the opening from it into the middle mea- 
tus being situated in the upper part of its nasal wall ; nor 
could it be emptied of its contents until the head was placed 
upon the opposite side. In case of a purulent discharge from 
the nose, a knowledge of this fact would enable the physician 
to determine whether it came from the antrum or not. 

The contents of the sphenoidal sinus, in case of a purulent 
collection, would be emptied entirely only when the head was 
placed with the face looking directly downwards. As the 
opening from the frontal sinus is in its floor, its contents 
would escape when the head occupied a vertical position. 
The nasal orifice of the ductus ad nasum should be observed, 
and the introduction of a probe of the proper curve into it 
should be practised upon the subject. The same thing should 
be done with the antrum and Eustachian tube. 

A correct idea of the dimensions of the nasal fossa is ex- 
ceedingly important. It will be observed that the upper part 
of it is very narrow, and will not admit an instrument of 
much size without injuring the parietes. 

The walls of the antrum. Fig. 51 (1 4), should be noticed as 



TOPOGRAPHY OF THE MOUTH. 143 

regards their thickness, and their relation to the month, the 
nose, the orbit, the pterjgo-maxillary fossa, and the face. 

The frontal sinus also demands attention, with reference to 
diagnosis, in diseases and injuries of it, and the proper treat- 
ment to be instituted, whether medical or surgical. 

Before dissecting the tongue, soft palate, pharynx, and 
larynx, the student should carefully examine the topography 
of the mouth, the fauces, and the pharynx. For this purpose, 
the head must be divided vertically, a little to one side of the 
median line, so as to avoid injuring the septum of the nose, 
as before directed, and at the same time leave the uvula 
entire. The back of the neck should be dissected before this 
section is made, in order that the upper cervical vertebrae 
may be divided with the head. It will not be necessary to 
divide the tongue or the larynx. The pharynx, however, 
should be opened along the median line posteriorly. 



Sect. XI. — Topogeaphy of the Mouth, Fauces, and 
Pharynx. 

The Mouth is the first division of the alimentary canal. 
It is exceedingly important, on account of the several func- 
tions with which it is associated. The organ of taste is located 
here ; the processes of mastication, insalivation, the articula- 
tion of sounds, and the commencement of deglutition, all 
take place in the cavity of the mouth. It is surrounded by 
movable walls, except the upper, and consequently is subject 
to great variation in its dimensions. When the lower jaw is 
applied to the upper, it is divided into two cavities; the outer 
one is situated between the cheeks and lips, and the teeth and 
alveolar processes; the inner one is embraced within the cir- 
cumference of the teeth and alveoli. The fornier receives the 
saliva secreted by the parotid glands; Avhile that secreted by 
the submaxillary and sublingual is jwured into the latter, thus 
securing a proper intermixture of tlie saliva with the Ibod. 
The external orifice of the mouth opens into the one, and the 
internal orifice opens out of the other into the fauces. The 
food is kept between the teeth until properly masticated, by 
the action of the lips and chocks on the outside, and the 



144 DISSECTION OF THE HEAD AND NECK. 

tongne on the inside of them. The lips are active agents in 
receiving food into the month, and the tongue is concerned 
in forcing it back into the pharynx. 

Both cavities are lined by mucous membrane, which is 
worthy of particular attention, as presented on the upper 
surface of the tongue, on the alveoli and hard palate, and 
in the other parts of the mon.th. 

The Lips are composed of the following structures : The 
orbicularis oris forms the middle and larger portion of their 
bulk ; it is covered on the outside by skin and subcutaneous 
areolar tissue; and, on the inside, by mucous membrane and 
submucous areolar tissue. They are abundantly supplied 
with arteries and nerves. The labial glands are situated on 
their inner side. The lips never contain adipose -tissue. 
Their great size in the African is owing mainly to the size 
of the orbicular muscle. 

The free borders of the lips in a state of health are of a 
bright red color ; but in an anaemic condition of the system, 
or when the blood recedes from the cataneous capillaries, 
they present a pale appearance. The study of the lips is 
very interesting and important to the artist, as they have so 
much to do in giving expression to the countenance. 

The Cheeks are composed of the same elements as the 
lips ; besides, they usually contain more or less adipose sub- 
stance. The principal muscle in each cheek is the bucci- 
nator. It is perforated opposite the second npper molar 
tooth by the duct of the parotid. Besides the small buccal 
glands beneath the mucous membrane, there are two quite 
large ones situated between the masseter and buccinator 
muscles ; these are called the molar glands. 

The fulness or plumpness of the cheeks depends partly on 
the fat which they contain, and partly on the presence of the 
teeth. The mucous membrane of the lips and cheeks is re- 
flected upon the alveolar processes, where it is blended with 
the fibrous structure beneath. It is here thick and dense, 
and possesses very little sensibility, as shown in infants, and 
in old people who have lost their teeth. It connects on the 
two sides of the alveolus, between the teeth and over the 
interalveolar septa. The gums are supplied with mucous 
follicles. Tartar, as it is called, is a product of these follicles. 



TOPOGKAPHY OF THE MOUTH. 145 

Tlie mucous membrane forms a fold on the inner side of 
eacli lip, which is called frgenum labii. 

In the posterior division of the buccal cavity, the mucous 
membrane and the papillse of the tongue are the principal 
things now to be examined. The portion covering the hard 
palate is similar to that of the gums. It is rough and uneven. 
Between it and the bone ramify vessels and nerves. It covers 
over and conceals the anterior and posterior palatine fora- 
mina. Between the alveolar processes of the lower jaw and 
the free border of the tongue it is thin, and loosely connected 
to the subjacent tissues. In the median line and on the un- 
der surface of the tongue it presents a fold, called \h.Q froenura 
linguce. This is so large and unyielding in some cases, that 
it interferes with the movements of the tongue. The diffi- 
culty is removed by dividing its free border. Just behind the 
incisor teeth, Fig. 53 (s), the mucous membrane is perforated 

Fig. 53. 




A View of the Lower Jaav, with the Tongue drawn upavards, so as to 
SHOW ITS under surface IN SITU. — 1, 2. The posterior superior surface of the 
tongue, with the papillre maxima). 3. The opening of the duct of the subniaxiUary 
gland, or the duct of Wharton. 4. The sublingual gland, seen under the mucous 
membrane of the mouth. 6. The lower jaw. 

by the excretory ducts of the sublingual and submaxillary 
glands. The upper surflice of the tongue is studded with 
papilhxi, Fig. 54, which render it quite rough. Thoro are 
two kinds of these papilhe. One sot is porlbratod, and the 
other is not. The former are situated near the base of the 
13 



146 



DISSECTION OF THE HEAD AND NECK. 



Fig. 54. 



tongue, and are of a glandular structure. They are arranged 
in two rows. The mucous membrane 
is not closely adherent to them, as it 
is to the true papillge. 

The true papillae are divided into 
three classes, as follows : — 

The calyciform consist of two rows 
which are arranged in the form of 
the letter Y. There are from six 
to eight in each row. They are situ- 
ated on the posterior part of the 
tongue. Each papilla is attached to 
the centre of a cup-like depression 
by its small extremity, leaving its 
large extremity free, and on a level 
with the surface of the tongue. At 
the junction of the two rows behind 
is a deep depression, called the " fora- 
men cgecum." It has opening into 
it several mucous follicles. Some- 
times a papilla is found in the place 
of it. 

The fungiform are found near the 
sides and tip of the tongue. They 
are of a reddish color, and much 
smaller than the preceding. They 
are best seen when a sapid substance 
is applied to the living tongue, as they 
then become distended. 

The conical pctpillce are diffused 
over the greater part of the dorsum 
of the tongue. They are inclined 

Tvhieh are seen the lamellated backwards, wllich bcCOmeS VCrV ap- 
and fnns:ed papillge. 5, 5. . -, .i , • i i i 

The V-shaped row of papillae parent whcu the tongue IS rubbed 
from behind forwards, especially in 
some of the lower animals. They are 
of a w^hiter color than the others. 

The papillge are very vascular, and 
are supplied with filaments from the 
"fifth and giosso-pharyngeal nerves. 

The Fauces, Fig. 55, is the space between the mouth and 




The Toxgue, with its Pa- 
pilla. — 1. The raphe, which 
in some tongues bifurcates on 
the dorsum of the organ, as 
in the figure. 2, 2. The lobes 
of the tongue. The rounded 
eminences on this part of the 
organ, and near its tip, are 
the papillge fungiformes. The 
smaller papillae, among which 
the former are dispersed, are 
the papillaj conies, and fili- 
formes. 3. The tip of the 
tongue. 4, 4. Its sides, on 



calyciformes. 6. The fora- 
men CEecum. 7. The mucous 
glands of the root of the 
tongue. 8. The epiglottis. 

9, 9. The freena epiglottidis. 

10, 10. The greater cornua of 
the OS hyoides. 



TOPOGRAPHY OF THE FAUCES. 



147 



tlie pharynx. It is bounded above by the soft palate, on 
eacli side by the anterior and posterior half- arches of 

Fig. 55. 




Median Section of the Nose, Mouth, Pharynx, and Larynx. — a. Septum of 
the nose; below it is the section of the hard palate, b. The tongue, e. Section of 
velum pendulum palati. d, d. Lips. n. Uvula, r. Anterior half-arch or pillar of 
fauces, i. Posterior half-arch. t. Tonsil, p. Pharynx, li. Hyoid bone. k. Thy- 
roid cartilage, n. Cricoid cartilage, s. Epiglottis, v. Glottis. 1. Posterior 
opening of nares. 3. Fauces. 4. Superior opening of larynx. 5. Passage into 
oesophagus. 6. Mouth of right Eustachian tube. 

the palate and the amygdaloid fossa, which contains the 
tonsil, and below by the base of the tongue. Its parietes are 
all movable, and contain muscular structure. The anterior 
half-arch^ Fig. 55, r, on each side is formed by the palato-glossus 
muscle and the mucous membrane reflected around it. It has 
nearly a vertical direction transversely. The posterior JiaJf- 
arch, Fig. 55, i, is formed by the palato-pharyngeus muscle. Its 
direction is downwards, backwards, and outwards. It pro- 
jects inwards more than the anterior. Between these half- 
arches is the amygdaloid fossa. It is of a triangular shape 
with the apex above. The lower part or base of it corre- 
sponds very nearly with the angle of the lower jaw. Its 



148 DISSECTION OF THE HEAD AND NECK. 

outer wall is formed hj the superior constrictor of the pha- 
rynx and tlie pharyngeal aponenrosis, by which the excava- 
tion containing the tonsil is separated from the internal 
carotid artery. 

The tonsil^ Fig. 55, t, is composed of a number of follicles col- 
lected into a group. Its internal surface is perforated by fora- 
mina which communicate with these follicles. A single fora- 
men may open into a cell or cavity with which several 
follicles communicate. In excising the tonsil when enlarged, 
there can be no danger of wounding the internal carotid if 
the incision be not made deeper than on a level with the half- 
arches. ISTor is there any danger of injuring the same artery 
in opening abscesses of the tonsil if the bistoury be not car- 
ried into it too far in a posterior direction, as the artery lies 
outside and between the tonsil and the vertebrae, on the 
rectus capitis anticus major. Abscesses of the tonsil almost 
always open internally on account of the resistance oftered 
by the pharyngeal aponeurosis. Mucus sometimes collects 
and becomes inspissated in the follicles, and when discharged 
gives rise to the idea that tuberculous matter has been expec- 
torated. The tonsil is supplied principally by the palatine 
branches of the pharyngeal arteries. These arteries some- 
times attain a considerable size in enlargements of the tonsils, 
and consequently may give rise to quite a profuse hemor- 
rhage when they are excised. 

The Phakynx, Fig. 55, ^9, is the third division of the ali- 
mentary canal. It extends from the cuneiform process of 
the occipital bone to a point opposite the fifth cervical verte- 
bra. It communicates with the tympana, nasal foss^, mouth, 
larynx, and oesophagus. Its position and relation to con- 
tiguous parts render an accurate knowledge of it exceedingly 
important. It may be very properly considered as divided 
into a nasal, a faucial, and a laryngeal section. This division 
is not based upon its structure, but upon its relations to the 
parts placed in front of it. Its posterior wall corresponds to 
the bodies of the superior five cervical vertebrae. This pre- 
sents nothing which requires to be noticed at the present 
time. Tlie same is true with the lateral walls, except at the 
upper part, where the orifices of the Eustachian tubes are 
found. The pharynx has no anterior wall peculiar to itself, 
bat is intimately associated with the nasal cavities, the fauces, 
and the larynx. 



TOPOGEAPHY OF THE PHAKYNX. 149 

Tlie posterior nares open into its npper part in a vertical 
direction. They are each about an inch in height, half an 
inch in breadth, and about three-fourths of an inch from the 
posterior wall of the pharjmx ; their surface is smooth, and 
they are slightly expanded, which facilitates the introduction of 
a plug, when this becomes necessary to arrest hemorrhage, and 
at the same time allows the plug to slip back into the pha- 
rynx, unless it be retained by the proper means in situ. It 
will be observed that in plugging the posterior nares, unless 
.the plug be adapted to their shape, the lower part of the ori- 
fice may be closed while the upper part will be left open. 

The pharyngeal orifice of each Eustachian tube will be seen 
a short distance behind, and to the outside of the nasal orifice. 
It is on a plane about one-fourth of an inch above the floor 
of the nasal fossa. It is somewhat expanded in the shape of 
a funnel, which readily admits a probe, or a tube for injecting 
the tympanum. Quite a deep sulcus in the upper and outer 
part of the pharynx should be noticed. It is just behind, 
and separated from the Eustachian orifice by a ridge. 

The Soft Palate and the Uvula, Fig. 55, c, w, projecting 
from the centre of its free border, may now be examined. It is 
a muscular organ, firmly attached to the posterior margin of 
the hard palate, and projecting backwards and downwards into 
the pharynx; it serves to extend the floor of the nasal fossae 
and roof of the mouth in this direction. It diminishes in 
thickness from before backwards, and assumes an arched 
form, with the concavity looking downwards and forwards. 
When elevated, it has a horizontal direction, and its free 
border is applied to the posterior wall of the pharynx, so as 
to form a septum between its upper and two lower divisions. 
The palate is marked on both of its surfaces in the middle by 
a whitish line or raphe. 

The Uvula has a conical shape, varies very much in size, 
and consists principally of mucous membrane and arcohir 
tissue, with a few longitudinal muscular fibres. It is pendu- 
lous, and, when not enlarged, its tip nearly touches tlie 
tongue, near the foramen ccecum. Its areolar tissue is lia- 
ble to be filled with serum in inflammation of thq tliroatj 
causing it to rest upon the tongue, and thus giving rise to a 
sense of titillation. Its wciglit, in these cases, may have a 
tendency to draw down the soft palate. 



150 DISSECTION OF THE HEAD AND NECK. 

At tlie lower part of tlie faucial opening in tlie pliarjnx, 
are two fossae or depressions, situated between tlie root of the 
tongue and tlie epiglottis, and separated from each other b}^ a 
fold of mucous membrane, called frsenum epiglottidis. These 
fossae are sometimes quite deep, and allow small bodies to 
lodge in them, whicli may give rise to irritation and spasmo- 
dic cougb. 

In the anterior part of tbe laryngeal portion of tbe pbarynx 
will be noticed the epiglottis, glottis, greater cornua of the 
byoid bone, posterior borders of the alse of tbe thyroid car- 
tilage, arytenoid, and cricoid cartilages. The exact location 
of each of these bodies is deserving of particular notice. 
They will be considered separately in connection with the 
larynx. The hyoid bone seems to belong both, to the tongue 
and the larynx. It will be described with the latter. 

Before leaving the cavities just described, it would be well 
for the student to study them carefully in their relations to 
each other, as in reference to introducing the stomach, tube, 
extracting foreign bodies from the pharynx or oesophagus, 
carrying an instrument into the larynx, either through the 
mouth or nose, opening abscesses in the pharynx, removing 
polypi or tumors about the posterior nares, &c. 



Sect. XII. — Dissection of the Palate. 

The soft palate contains five pairs of muscles. These are 
exposed, and their arrangement seen by very little dissec- 
tion, which may be done after the removal of the pharynx. 

The palatine aponeurosis is a fibrous prolongation from the 
posterior margin of the hard palate. It diminishes in thick- 
ness as it descends towards the free border. It is connected 
with the tendons of the palatine muscles, and forms a sort of 
framework for the palate. 

The AzYGOS UvuL^, Fig. 57 (s), consists of two vertical 
fasciculi, which arise from the centre of the free border of 
the hard palate, and extend to the tip of the uvula. In ex- 
cising the uvula, the mucous membrane should not be made 
tense; if it be done, the fibres of this muscle may project 
from the wound after the membrane has retracted. 

The Levatok Palati, Pig. 56 (2, 3), consists of a vertical 



DISSECTION OF THE PALATE. 



151 



and a liorizontal portion. The vertical part is situated behind 
the Eustachian tube, and outside the corresponding posterior 
naris. It arises from the petrous portion of the temporal 
bone, near its apex, and from the contiguous part of the 
Eustachian tube. Its fibres pass downwards, on the outside 
of the tube, and then turn inwards to be inserted^ with its 
fellow, on the opposite side, along the median line of the 
palate. 

The Tensor Palati arises^ Fig. 56 (4), from the scaphoid 
fossa at the upper part of the internal pterygoid ala, from a 
small portion of the great wing of the sphenoid, and from the 
Eustachian tube. Its fibres pass downwards to the hamular 
process, where they form a small round tendon, which winds 
round this process, and is reflected horizontally to the me- 
dian line of the palate, into which it is inserted. Where it 
plays over the pully-like surface of the hamular process, 
there is a synovial membrane. Its vertical portion is situated 
between the internal pterygoid and levator palati muscles. 



Fig. 57. 




A View of the Muscles op the 
Soft Palate, as seen from below 
AND IN front. — 1. The roof of the 
mouth, or hard palate, sawed across at 
the second mohir tooth. 2. Origin of 
the levator palati muscle. 3. Its ex- 
pansion near its insertion. 4. Origin 
of the circumflexus or tensor palati. 
6. The pterygo-maxillary ligament, 
which converts the notch througli which 
this muscle plays into a foramen. 6, 
6. Palatine aponeurosis. 7. A section 
of the constrictor pliaryngis superior 
muscle. 8. Extremity of the azygos 
uvuh\> muscle. 9. Section of the Eus- 
tachian tube. 



A Posterior View of the Muscles 
OF THK Soft Palate, as shown by a 

SECTION OF THE CuANIUM THROUGH THE 

Glknoio Caa^itiks. — 1. Basihir portion 
of the sphenoid bone. 2. Condyles of 
lower jaw. 3. Hard palate. 4. Levator 
palati, on one side entire, on the other 
partially removed. 5,5. Eustachian tubes. 
6. External pterygoid muscle. 7. Cir- 
cumnoxus palati. 8. A/.ygos uvuUw 5), 
IMyloid attachment of constrictor pharyngis 
superior. 10. Palato-pharyngeus. II. 
Palato-glossus. 



The Palato-glossus, Fig. 57 (i i ), is a small, pale fasciculus, 
which is spread out above in the soft palate and below in 



152 DISSECTION OF THE HEAD AND NECK. 

tlie side of the tongue. Its middle portion forms tlie anterior 
half arch of the palate. It is situated immediately beneath 
the mucous membrane. 

The palato-pharyngeus^ Fig. 57 (lo), is described with the 
muscles of the pharynx. 

The arteries of the soft palate, or velum palati, are branches 
of the superior and inferior pharyngeal, and of the internal 
maxillary. 

The nerves are derived from the ganglion of Meckel, and 
from the glosso-pharyngeal. 

The cartilaginous jportion of the Eustachian tube may now 
be dissected. This tube, altogether, is about two inches in 
length. It establishes an open communication between the 
tympanum and -pharynx. Its direction being downwards, 
forwards, and inwards, facilitates the escape of mucus from 
the tympanic cavity into the pharynx. The cartilaginous 
portion is about sixteen lines in length. It is much smaller 
where it unites with the osseous portion of the tube than at 
its pharyngeal orifice. It is attached to the sides of the groove 
formed by the petrous and spinous portions of the temporal 
and sphenoid bones. The outer and anterior part of the tube 
consists of a fibrous structure. The mucous lining of the 
tube is quite delicate, except at its orifice, where it resembles 
that of the pharynx. The position and large size of this 
opening deserve particular notice, with reference to the in- 
troduction of instruments. 

Sect. XIII. — Dissection of the Tongue. 

The Tongue is a muscular organ, capable of being moved 
in difierent directions, and of varying its form and dimensions. 
Divided in the median line, it presents two halves in every 
respect alike. It does not entirely fill the space within the 
curve of the teeth and alveolar processes. It diminishes in 
thickness from behind forwards. The anterior part of it is 
covered wholly by mucous membrane, and not only moves 
freely in the mouth, but can be protruded from it. The 
mucous membrane, with the papillae, were described with the 
topography of the mouth. 

The frameiuork of the tongue consists of the hyoid bone, 
a hard cartilaginous substance situated in the median line, 



DISSECTION OF THE TONGUE. 



153 



and a dense fibrous layer beneath, tbe mucous membrane 
of the dorsum. Fig. 58. 

The Intrinsic Muscles of the tongue consist of muscular 
fibres having a longitudinal, transverse, and vertical direc- 
tion. The longitudinal fibres are situated near its upper and 



Fig. 58. 




A View of the DoRSirsr of the 
Tongue, from which, by maceration, 

THE PeRIGLOTTIS HAS BEEN REMGYED, 
AND TURNED BACK ON THE RiGHT SiDE. 

— 1. The side of the tongue. 2. Its 
base. 3. Its tip or point. 4. The de- 
nuded portion of the tongue, showing 
the papillge deprived of the epidermis 
or periglottis. 5. The under surface of 
the detached epidermis, showing its 
depressions. 6. Foramen Cajcum. 7. 
The truncated papillae near it. 8. The 
other papillfe, denuded of the epidermis. 
9. Impression of the periglottis around 
the denuded papillae. 10. Fra^num to 
the epiglottis cartilage. 11, 12. De- 
pressions on the periglottis which fits 
the elevations on the tongue. 



Fiff. 59. 




A View of the Muscles of the 
Tongue, as seen on its Lower Sur- 
face. — 1. Bod}' of the OS hyoides. 2,2. 
Styloid processes of the temporal bones. 
3. Horizontal portion of the stylo-glossus 
muscle. 4. The hyo-glossus. 5.^ The 
genio-hj^o-glossus held up by a hook 
near its origin. 6. Section of the glos- 
sal portion of the same muscle. 7. Its 
insertion into the os hyoides. 8. The 
middle fissure and fatty matter between 
the muscles of each side. 9. The lingu- 
alis muscle. 10. The transversales liu- 
gu£e at the point of the tongue. 



lower surfaces, and have been called the superior and in- 
ferior lingual muscles. Fig. 59 (9). Their origin and termina- 
tion are not very distinct. The transverse. Fig. 59 (1 0), and 
vertical fibres are seen throughout the substance of the 
tongue ; the former passing from one side to the other, and 
the latter from the dorsal to the under surface. 

The extrinsic muscles are those which have their 



on u'ui 



outside of the body the tongue. They are the following : — 



15i 



DISSECTION OF THE HEAD AND NECK. 



Fig. 60. 



The Stylo-glossus, Fig. 59 (3), arises from the styloid pro- 
cess and stylo -maxillary ligament^ and, passing downwards, 
inwards, and forwards, enters the side of the tongue, where it 
spreads out and divides into an internal and external portion. 
The latter runs to the apex, while the former takes a trans- 
verse direction, and terminates by intermixing with the in- 
trinsic fibres. 

The Hyo-glossus, Fig. 59 (4), arises from the body and 
great cornu of the hyoid bone, and enters the tongue between 
the lingualis and stylo-glossus. The greater part of this 
muscle is seen in the dissection of the submaxillary region. 

The GrENio-HYO-GLOSSUS, Fig. 60 (4), is the largest of the lin- 
gual muscles. It arises from the lower 
jaw, near the symphysis. Some of its 
fibres pass downwards and backwards, 
and are inserted into the hyoid bone. 
The rest of the fibres, with the excep- 
tion of a few which spread out upon the 
side of the pharynx, go to the tongue. 
They have a vertical direction, and 
extend the whole length of the tongue 
near the median line, spreading out 
in the shape of a fan. At the base 
of the tongue, the genio-hyo-glossi 
muscles are separated from each other 
merely by cellulo-adipose substance. 
The J9a?(2to-^?05sw5 was noticed in the 
dissection of the palate. 

The arteries of the tongue are, the 
lingual and branches of the palatine 
and pharyngeal. The lingual, in the 
latter part of its course, is called the 
ranine artery. The sublingual^ com- 
monly a branch of the lingual, passes 
between the mylo-hyoideus and genio- 
hyo-glossus muscles, and sends 
branches to the sublingual gland and 
to the frgenum linguae. Branches 
proceed from the lingual artery to every part of the sub- 
stance of the tongue. 

The nerves are supplied from the hypoglossal, glosso-pha- 
ryngeal, and the gustatory branch of the fifth. The hypo- 




A View of the Uxder 
Surface of the Toxgue, 
WITH THE Muscles connect- 
ed WITH it. — 1, 1. The infe- 
rior surface of the tongue. 
2. The OS hyoides. 3, 3. Ori- 
gin of the hyo-glossus muscle. 
4, 4. The genio-hyo-glossus 
of each side dissected off and 
turned to one side. 5, 5. The 
white central vertical septum 
of the tongue. 



SUPEEFICIAL PARTS OF THE NECK. 155 

glossal is distributed to the muscles ; the glosso-pharyngeal 
to the mucous membrane at the back part of the tongue; 
and the gustatory branch of the fifth to the mucous mem- 
brane on its sides and tip. 



CHAPTER II. 

DISSECTION OF THE NECK. 

Sect. I. — Superficial Parts of the Neck. 

The posterior part of the neck should be dissected with 
the back, as they have several muscles in common, and also 
on account of the similarity in the arrangement of their ves- 
sels and nerves. 

The anterior part of the neck is a very important region, 
and demands the special attention of the student in the dis- 
secting-room. In it are found the larynx, trachea, pharynx, 
oesophagus, and numerous vessels and nerves. 

Each side is bounded above by the base of the inferior 
maxilla, the lower border of the parotid region, and the 
mastoid process of the temporal bone ; posteriorly, by a line 
extending from the occiput, j ust behind the mastoid process, 
to the acromion process of the scapula; and below, hy the 
acromion process and the upper border of the clavicle and 
sternum. The two sides are divided by the median line. 
One side should be dissected at a time. 

To dissect this region, the thorax should be elevated and 
the position of the head changed from time to time, as it may 
be found necessary to have the parts relaxed or made tense. 
The dissector must exercise his own judgment in determining 
the best position for the head in the different stages of the 
dissection. As a general rule, muscles should bo made tense 
to facilitate their dissection, but sometimes, in separating 
them from each other, or when tracing vessels and nerves 
among them, it is better that they should be relaxed, so that 
they can be drawn to one side or lifted up. 

Beibre commencing the dissection, the student should ob- 



156 DISSECTION OF THE KECK. 

serve the following prominent points in the median line, and 
the distances they are apart: The chin, the hyoid bone, the 
thyroid and cricoid cartilages, and the sternum. If the sub- 
ject be emaciated, he will also be able to feel distinctly the 
cartilaginous rings of the trachea. It is an excellent plan 
for the student to familiarize himself with all the prominent 
points in a region which can be seen or felt in the living 
body. If they be movable, then he should attentively ob- 
serve the changes effected by such movements in their rela- 
tions to each other and to the surrounding parts. 

A vertical incision is to be made along the median line, 
through the skin, from the symphj^sis of the chin to the 
upper border of the sternum; and, if the face and thorax 
have not already been dissected, two horizontal ones will be 
required; a superior one, extending from the commencement 
of the first, along the base of the inferior maxilla, to the 
mastoid process; and an inferior one, commencing at the 
termination of the first, and continued along the upper border 
of the clavicle, to the acromion process. In making these in- 
cisions, care should be taken to divide nothing but the skin. 

The skin is to be carefully dissected up and reflected back- 
wards, leaving the superficial fascia exposed. The platysma 
myoides is placed between two layers of this fascia. The outer 
layer is very thin in the lower part of the neck, but quite 
thick in the upper part, where it usually contains a consider- 
able quantity of adipose tissue. When the fat is very abund- 
ant, it forms what is called the double chin. There are no 
vessels of any importance in this layer, and the only nerves 
found in it are cutaneous branches derived from the cervical 
plexus. This layer may now be removed, and the platysma 
myoides exposed. 

To raise the fascia, the student should commence at the 
chin, and cut down cautiously until he perceives the muscle 
and observes the direction of its fibres. Having found the 
muscle, and made its fibres tense by placing the head in a 
proper position, there can be no difficulty in dissecting off 
the fascia and leaving the muscle clearly exposed. The 
strokes of the scalpel must be made, at first slowly and care- 
fully, in the direction of the fibres. If the student attempts 
to make a rapid dissection of this muscle, he will be very 
likely to remove more or less of it with the fascia. 



SUPERFICIAL PARTS OF THE NECK. 



157 



The Platysma Myoides arises, Fig. 61 (i 4), from the pec- 
toral and deltoid fasciie, just below the clavicle. Its fibres 

Fig. 61. 




A Side View of the Superficial Layer of Muscles on the Face and Neck. 
— 1. Tendon of the occipito-frontalis. 2. Its frontal belly. 3. Attrahens aiireni. 
4. Attollens aurem. 5. Occipital belly of the occipito-frontalis. 6. Retrahens 
aurem. 7. Orbicularis palpebrarum. 8, 8. Levator labii superioris aUvque nasi. 
9. Compressor naris. 10. Levator anguli oris. IL Buccinator. 12. Zygomaticus 
minor. 13. Orbicularis oris and zygomaticus major. 14, Platysma myoides. 15. 
Splenius. 16. Masseter. 17. Sterno-cleido-mastoid. IS. Levator scapuhv). 19. 
Scalenus medius. 20. Trapezius. 

pass upwards and somewhat forwards over the neclc, and 
are lost in the lower part of the face; some of them decussate 
at the symphysis of the chin with the corresponding fibres 
on the oi)posite side ; others end in the skin, or blend with 
some of the muscles of the mouth, as described in the dissec- 
tion of tlie lace. This muscle seems to be, in the luuuau 
11 



158 ^ DISSECTIOK OF THE NECK. 

body, a vestige of the panniculus carnosus of the lower 
animals. 

The platysma may now be dissected up from the layer of 
fascia beneath it, when the follomng vessels and nerves must 
be found and studied: — 

The External Jugular Vein, Fig. 2, f, and Fig. 62 
(i, 2, 3), formed generally by the union of the temporal and 
internal maxillary veins, commences close to the angle of 
the lower jaw, and passes downwards and backwards over 
the sterno-cleido-mastoideus, towards the centre of the cla- 
vicle, and terminates usually in the subclavian. It is some- 
times very small or entirely absent; again, it is very large and 
sometimes double. It may be large on one side and small on 
the other. It also varies in its origin and in its termination. 
As this vein is sometimes opened for the abstraction of blood, 
it should be particularly noticed. Its direction, in connection 
with that of the fibres of the platysma, should be observed 
with reference to the proper mode of opening the vein. It 
commonly contains two valves — one near its centre and the 
other near its termination; the first is sometimes wanting. 

The Facial Yein, Fig. 62 (1 e), enters the neck along with 
the facial artery, and passes down in front of the submaxillary 
gland, while the artery goes behind it. It most commonly 
unites with the lingual to form a common trunk which opens 
into the internal jugular. Its termination, however, is so irre- 
gular, and of so little consequence, as to deserve no special 
attention. 

The Anterior Jugular, Fig. 2, A, commences in the 
submaxillary region, and, passing down on the anterior part 
of the neck to the upper border of the sternum, dips beneath 
the sterno-cleido-mastoideus to reach the subclavian. Some- 
times, there is no anterior jugular, or it is very small; some- 
times, it is quite large on one side and very small on the 
other; again, it may take the place of the external jugular, 
which will, in that case, be absent. If the student should have 
an opportunity to dissect the superficial veins of the neck in 
several subjects, he will observe the great irregularity which 
exists in their general arrangement. 

The Facial Artery, Fig. 62 (14), is the only one which 
deserves any special notice in connection with the superficial 



SUPERFICIAL PARTS OF THE NECK. 



159 



fascia. This artery will be seen passing over the base of the 
inferior maxilla, just in front of the insertion of the masseter, 

Fig. 62. 




A Side View of the Superficial Arteries and Veins of the Face and Neck. 
• — 1. External jugular vein, seen under the platysma niyoides muscle. 2. Anasto- 
mosing branch from the cephalic vein of the arm to the external jugular. 3. Ex- 
ternal jugular after the removal of the platysma muscle. 4. Communication of the 
external and internal jugulars by means of the fixcial vein. 5. Occipital vein and 
branches. 6. Occipital artery. 7. Posterior auricular artery and vein. 8. Point 
where the external jugular is formed by the union of the temporal and internal 
maxillary veins. 9. Temporal artery and parietal vein. 10. Frontal branches of 
the same J on the top of the head are seen the anastomoses of these vessels with the 
occipital. 11. Internal jugular vein. 12, Superior thyroid artery and vein. 13. 
Lingual artery and vein. 14. Facial artery. 15. Point of its anastomosis with the 
nasal branch of the ophthalmic. 16. Facial vein separated from the artery, except 
at its origin and termination. 17. Inferior coronary artery and vein. 18. Superior 
coronary artery and vein. 19. Ascending nasal vein. 20. Nasal branches of the 
ophthalmic artery and vein. 21, 22. Frontal vein. 

or aboat an inch from the angle of the jaw. The suhmcntal 
branch^ Fig. 1 (s), of the facial usually passes up over the 
lower jaw, near the symphysis of the chin. 



160 



DISSECTION OF THE NECK. 



The nerves are, the occipitalis minor, the anricularis mag- 
nus, the snperficialis colli, the cervical branches of the facial, 
and the snpra-clavicular branches. 

The Occipitalis Minor, Fig. 63 (is), is a small nerve 
which passes upwards along the posterior border of the 
sterno-cleido-mastoideus to the occiput. 

The AuRicuLAEis Magnus, Fig. 63 (12), arises from the 
second and third cervical nerves, near the middle of the neck, 
winds obliquely upwards and forwards over the posterior 
border of the sterno-cleido-mastoideus, and goes up to the 

Fia;. 63. 











A View of the Facial Nerve, together with the Branches of the CERVicAii 
Plexus, Ac. — 1. The portio dura, or facial nerve, escaping from the stylo-mastoid 
foramen; the parotid gland has been removed, in order to show the nerve more 
clearly. 2. Its posterior auricular branch. 3. The stylo-hyoid branch, 4. The 
pes anserinus. 5. Temporal branches of the facial nerve. 6. Malar branches. 7. 
Cervico-facial branches. 8. Supra-orbital nerve. 9. Subcutaneus malae, a branch 
of the superior maxillary nerve. 10. The infra-orbital nerve. 11. Terminal branches 
of the inferior dental nerve. 12. Nervus auricularis magnusof the cervical plexus. 
13. The superficialis colli nerve. 14. The plexus formed between the superficialis 
colli and the branches of the facial. 15. The occipitalis minor, a branch of the cer- 
vical plexus. 16. Descending branches of the cervical plexus. 17. The phrenic 
nerve. 18. The spinal accessory of the eighth pair. 19. The great or posterior 
occipital nerve. 



SUPEEFICIAL PARTS OF THE NECK. 161 

parotid region, crossing in its course tlie sterno-cleido-mas- 
toideus. It is generally found a short distance behind the 
external jugular vein, and running nearly parallel to it. Its 
terminal branches were dissected in connection with the paro- 
tid and auricular regions. 

The SuPERFiciALis Colli, Fig. 63 (i 3), arises at the same 
place as the auricularis magnus, passes over the sterno-cleido- 
mastoideus, and, going transversely across it and beneath the 
external jugular vein, divides into ascending and descending 
tranches. The former ascend to the submaxillary region; 
one or two filaments usually accompany the external jugular 
vein, and two or three filaments anastomose with the facial 
beneath the platysma. The latter ramify on the side of the 
neck, extending to the median line. The superficialis colli 
sometimes arises, by two trunks, from the cervical plexus. 
The filaments which accompany the external jugular may be 
wounded when this vein is opened. 

The Cervical Branch of the Facial, Fig. 63 (1 4), leaves 
the parotid gland near the angle of the lower jaw, beneath 
which it passes to the anterior and upper part of the neck to 
near the chin, where it divides into several branches. It 
runs beneath the platysma, to which it sends filaments. Two 
or three branches anastomose, as before stated, with the super- 
ficialis colli, with which they form a plexus. 

The Supra-Clavicular and Acromial Nerves, Fig. QQ 
(1 e), arise from the cervical plexus, behind the sterno-cleido- 
mastoideus, and divide into anterior, middle, and posterior 
branches. The anterior pass downwards and forwards, over 
the sterno-cleido-mastoideus, to the anterior and lower part 
of the neck, and, over the inner part of the clavicle, to the 
thorax; the r)%iddle go directly downwards to the clavicle, 
which they pass over to reach the thorax ; the posterior or 
acromial branches pass over the lower portion of tlic trapezius, 
and the acromion process and spine of the scapula, to the 
shoulder. These nerves are distributed to the platysma 
myoides and to the integument. 

The superficial, fascia of the neck may be regarded as con- 
sisting of the dense areolar tissue Avhicli is S],)read out beneath 
the skin, being continuous, above, with the superficial fascia 
of the face, and below with that of tlie thorax, and containing 



162 DISSECTION OF THE NECK. 

tlie subcutaneous vessels and nerves, tlie platysma myoides, 
and lymphatic glands ; while the deep cervical fascia is more 
dense in its structure, has fixed attachments, and contains 
between its laminse the deep vessels, nerves, and lymphatic 
glands, and the muscles. The superficial fascia forms a bond 
of union between the skin and the deep parts, and retains in 
situ the subcutaneous vessels, &c. The deep fascia connects 
together the deep parts, and keeps each one in its proper 
place. It must be studied as these parts are exposed in the 
progress of the dissection. 

The superficial fascia may now be raised without preserv- 
ing the vessels and nerves found in it. This can be done on 
the opposite side. The following muscles may now be dis- 
sected : — 

The Steeno-Cleido-Mastoideus, Fig. 64 (17), is the 
largest muscle on the side of the neck. It is separated from 
the platysma myoides by the deep layer of the superficial 
fascia, the external jugular vein, the auricularis magnus, 
the superficialis colli, and the anterior branches of the supra- 
clavicular nerves, which have already been dissected, and by 
a thin layer of the deep cervical fascia. This layer of the 
deep fascia is frequ.ently so thin, that it is difiicult to dissect 
it up as a distinct lamina ; its continu.ity, however, with the 
deep fascia, especially at the anterior border of the muscle, 
will be clearly seen. It arises by two heads ; one from the 
upper border of the sternum, and the other from the inner 
extremity of the clavicle. The sternal origin is the narrow- 
est, and extends tendinous for some distance ; the clavicular 
origin varies very much in width in different subjects, and 
its tendinous fibres are shorter. The space between these 
two heads is occupied by areolar tissue ; it also varies very 
much in width in different su.bjects; sometimes it is scarcely 
perceptible. The muscle formed by the junction of these 
two heads passes obliquely upwards and backwards, and is 
inserted into the mastoid process and the superior semicir- 
cular ridge of the occipital bone. The action of the two 
muscles is to approximate the chin to the sternum; if one 
acts alone, it will turn the chin to the opposite side. 

This muscle is exposed by making an incision through the 
fascia, near its anterior border, from its origin to its insertion, 
and dissecting the fascia off, so as to observe its connection 
with the deep layer. 



SUPEEFICIAL PAETS OF THE NECK. 163 

The Steeno-Hyoideus, Fig. 64 (i e) and Fig. 69 (i 4), arises 
from the posterior surface of the sternum, sometimes in part 
from the sterno-clavicular ligament and the clavicle, or the 
cartilage of the first rib. It passes upwards, and is inserted 
into the body of the hyoid bone. It is quite thin, and from 
half an inch to three-fourths of an inch in breadth. It is 
separated from its fellow on the opposite side by a thin layer 
of fascia, especially in front of the trachea and thyroid gland. 
The proximity of these mascles should be noticed with refer- 
ence to tracheotomy. 

The Omo-Hyoideus, Fig. 64(i6), is a digastric muscle; 
its two bellies being connected by a small tendon behind the 
sterno-cleido-mastoideus. Its posterior belly arises from the 
upper border of the scapula, near the coracoid notch, and 
sometimes from the ligament subtending the notch ; its ante- 
rior belly arises from the body of the hyoid bone. The di- 
rection of each belly deserves notice. The anterior one, it 
will be observed, corresponds in its direction very nearly to 
a line extending from the body of the hyoid bone to the 
centre of the clavicle. The posterior belly is more transverse 
in its direction. The tendon, common to these two bellies, is 
situated in the deep cervical fascia, and so connected with it 
as to render the fascia tense when the bellies contract. 

Before dissecting the origin of the posterior belly, the an- 
terior and lower portion of the trapezius may be exposed, 
and detached from the clavicle and acromion process. This 
part of the trapezius, Fig. 64 {2 2\ should be dissected now, so 
that its relation to the supra-clavicular region may be seen. 

The Steeno-Thyeoideus, Fig. 69 (is), arises from the 
posterior surface of the sternum, and sometimes in part from 
the cartilage of the first or second rib. It passes upwards 
and is inserted into the oblique ridge on the ala of the thj^roid 
cartilage. It is placed behind the sterno-hyoideus, project- 
ing some distance beyond its external border. It does not, 
however, like that muscle, approximate closely to its fellow 
on the opposite side, and hence it is not directly concerned 
in the anatomy of tracheotomy. It is considerably broader 
than the sterno-hyoideus. 

The TnYEO-HYOiDEUS, Fig. 64 (1 r>), is a short muscle which 
arises from the thyroid cartilage, and passes over the thyro- 
hyoid space, and is inserted into the hyoid bone. It appears 



164 



DISSECTION OF THE NECK. 



to be a continuation of tlie sterno-tLyroideus, and iinless the 
student is on his guard, it will be dissected up with that 
muscle. 

Fig. 64. 




A Lateral View of the Deep-seated Layer of Muscles on the Face axd 
Neck. — 1. Temporal muscle deprived of its fascia. 2. Corrugator Supercilii. 3. 
Pyramidalis nasi. 4. Superior or nasal extremity of the levator labii superioris alae- 
que nasi. 5. Compressor naris. 6. Levator anguli oris. 7. Depressor labii superioris 
alasquenasi. 8. Buccinator. 9. Orbicularis oris. 10. Depressor labii inferioris. 11. 
Levator labii inferioris. 12. Anterior belly of the digastricus. 13. Mylo-hyoid. 
14. Stylo-hyoid. 15. Thyro-hyoid. 16. Upper belly of the Omo-hyoid. 17. 
Sterno-cleido-mastoid. 18. Sterno-hyoid. 19. Scalenus anticus. 20. Pectoralis 
major. 21. Deltoid. 22. Trapezius. 23. Scalenus Medius. 24. Levator sea- 
pulse and scalenus posticus. 25. Splenius. 26. Complexus. 

If the dissector should find it necessary to detach either 
of these muscles at one of their extremities, in order to ex- 
pose another, it should be done so that the muscle can be 
replaced again in its natural position. The sterno-cleido- 
mastoideus can be detached at its origin, and raised up for 



SUPEKFICIAL PAETS OF THE NECK. 165 

some distance, witliout injuring anything of importance. 
The sterno-hyoideus may also be detached at its origin and 
turned upwards, so as to dissect the muscle beneath it. 

The actions of the three last muscles will be readily un- 
derstood by observing their attachments. 

The sterno-, thyro-, and omo-hyoid muscles, Fig. 67 (e), re- 
ceive nervous filaments from the descendens noni ; the thyro- 
hyoid is supplied by a filament from the hypoglossal. These 
nerves may be looked for while dissecting the muscles, or 
their examination may be postponed until the opposite side 
is dissected. The same course may be pursued with regard 
to the arteries going to them. 

The DiGASTRicus, Fig. 69 (i, 2), arises from the digastric 
fossa and mastoid process, and from the base of the inferior 
maxilla close to the symphysis ; the two bellies are inserted 
into an intermediate tendon, which is connected by tendinous 
fibres to the hyoid bone. The posterior belly is the longest 
and more transverse in its direction. The tendon of this 
muscle perforates the anterior extremity of the stylo-hyoideus^ 
A little care is necessary, or this arrangement may be de- 
stroyed before it is observed. The deep fascia of the neck 
is connected to the digastric muscle, which deserves to be 
noticed. The origin of the posterior belly of this muscle 
need not be exposed at present, as it is covered by the sterno- 
cleido-mastoideus. The action of this muscle is to depress 
the lower jaw, or, when this is fixed, to elevate the hyoid 
bone. 

If the student has been successful thus far in his dissection 
of the neck, he will encounter but little dif&culty in com- 
pleting it in a manner satisfactory to himself. All the more 
prominent points are now distinctly brought into view, and 
their relations to the other parts are such that he will be able 
to locate and find them without much trouble. He can now 
readily trace upon the subject the boundaries of the follow- 
ing subdivisions or surgical regions. 

Each side of the neck is divided into five regions ; the 
submaxillary, the superior carotid, the inferior carotid, the 
supra- clavicular, and a fifth one, which is situated behind the 
sterno-clcido-mastoideus, and above the posterior belly of the 
omo-hyoidcus muscle. 

The Submaxillary Eegion is bounded above by the in- 



166 DISSECTION OF THE XECK. 

ferior maxilla, below and in front by the anterior belly of 
the digastricus, below and behind by the posterior belly of 
the same moscle. and by a process of the deep fascia, which 
is attached to the stylo-maxillary ligament, and separates this 
region from the parotid. 

The SuPERioPw Caeotid Eegiox is bounded above by the 
posterior belly of the digastricus. behind by the stemo-cleido- 
mastoideus, below and in front by the anterior belly of the 
omo-hyoideus. 

The IxFEEiOE Caeotid EE'3-iox is bounded anteriorly by 
the median line, above by the anterior belly of the omo- 
hyoideus, and behind and below by the stemo-cleido-mas- 
toideus. 

The Supea-Claticulae Eegiox is bounded in front by 
the sterno-cleido-mastoideus, above by the posterior belly of 
the omo-hyoideus, and below by the clavicle. 

The Fifth Eegiox, or Sub-Occipital, is bounded in front 
by the sterno-cleido-mastoideus, below by the omo-hyoideus, 
and behind by the trapezius. 

A sixth regiryn^ embracing the parts concerned in the opera- 
tions of laryngotomy and tracheotomy, or laryngo-tracheo- 
tomy, may be conveniently made by the student. It is not 
necessary, however, to give any specific boundaries to such 
a region. 

The lower part of the neck, embracing the inferior carotid 
and supra -clavicular regions, and extending upwards to the 
bifurcation of the common carotid aitery, is to be dissected 
next. 

If the sterno-cleido-mastoideus. st^rno-hyoideus, and stemo- 
thyroideus have not been detached at their origins, it should 
be done now. The overlapping of the sternal origin of the 
sterno-cleido-mastoideus should be noticed, with reference to 
ligation of the common carotid artery. Beneath the sterno- 
hyoid and thyroid are the trachea and thyroid gland. A 
]jlexus of veins. Fig. ^(^^ coming from the thyroid gland, is 
usually situated directly in front of the trachea, and is liable 
to be wounded in tracheotomy. 

The middle thyroid artery^ sometimes called the artery of 
iS eubauer, when present, is found in this region. It is not 
very often met with, and is so irregular in its origin and 



SUPERFICIAL PARTS OF THE NECK. 167 

course, that no rule can be laid down for avoiding it in 
opening tlie windpipe. There are no nerves in front of the 
trachea which deserve any special notice. It is separated 
from the muscles by a layer of the deep fascia, by areolar 
tissue, and by the thyroid gland. 

The Thyroid G-land consists of two lobes, connected 
across the upper rings of the trachea, usually the second and 
third. It is of a reddish color and exceedingly vascular. 
The lobes are situated more on the sides than in front of the 
trachea. They are somewhat conical in shape; the small 
end being above. Each one extends from about the sixth 
ring up to the thyroid cartilage, and projects backwards 
between the sheath of the common carotid and the wind- 
pipe. The portion connecting the two lobes is called the 
isthmus. This varies much in size, a point which deserves 
special notice in reference to tracheotomy. A small body 
projects upwards from the isthmus, or from one of the lobes 
called the pyramid^ and this again is connected to the hyoid 
bone by a fibrous structure, which, from its resemblance to 
muscle in some cases, has been called the levator glandulce 
thyroidece. 

There is perhaps no organ in the body which presents so 
great a variety in its development as the thyroid gland. It 
is not necessary to specify these variations, as the student 
will be able to note them as he happens to meet with them 
in his dissections. Whatever may be the office of the 
thyroid gland, whether of great or little importance in the 
economy, it is liable to abnormal or pathological changes, 
which are of the utmost consequence to the physician. 

It has no excretory duct, and, consequently, cannot be 
classified with the true glands which elaborate and secrete a 
known fluid. Its arteries are derived from the subclavian 
and external carotid. At this stage of the dissection, the 
student will observe merely the terminal branches of the 
thyroid arteries. Those of the inferior thyroid will be seen 
entering for the most part the under surface of the lower 
portion of the gland, while those of the superior penetrate 
the anterior surface of the upper part. This mode of en- 
tering the gland seems to result from, or at least to corre- 
spond to, the superficial and deep situation oC the superior 
and inferior thyroid arteries. 



168 DISSECTION OF THE NECK. 

The veins go to form the tracheal plexus, which has been 
alluded to in connection with the anterior relations of the 
trachea. 

The anterior part of the larynx may now be noticed, espe- 
cially the crico -thyroid space, as connected with the opera- 
tion of laryngotomy. A small artery crosses this space 
transversely, resting upon the anterior crico-thyroid liga- 
ment, and sending a branch through it to the mucous mem- 
brane. The anterior portion of the cricoid and thyroid 
cartilages shou.ld also be inspected in situ. 

AYhen the parts in front of the trachea and larynx have 
been duly examined, the dissection is to be continued in a 
lateral direction. As the two sides of the neck differ in this 
region in some material points, the right side will be examined 
first, and the peculiarities of the left will be noticed in an- 
other place. 

The first thing to be sought in this region is the Arteeia 
Innominata, Fig. QQ (i o). This will be found immediately 
beneath the sterno- clavicular articulation, covered by fascia. 
Only the upper portion of it will be seen in the dissection of 
the neck. When its bifurcation into the comm.on carotid and 
the subclavian is found, the sheath of the former may be laid 
open to near its division into the external and internal caro- 
tids. Before doing this, however, the relation of the omo- 
hyoideus to the artery should be observed ; also, the course 
of the descendens noni nerve., which lies upon the sheath com- 
mon to the artery and internal jugular vein. Some small 
nervous filaments will be noticed crossing the artery, and 
which are liable to be divided in ligating it. Having exposed 
the common carotid, the following parts will be found with- 
out difficulty : — 

On the outside, and running parallel to it, is the Internal 
Jugular. As this vein is traced downwards, it will be seen 
that it does not terminate at the commencement of the carotid, 
Pig. QQ) (i e), but passes over the subclavian artery to join the 
subclavian vein, and with it form the vena innominata. By 
separating the carotid from the jugular vein, the -pneumo- 
gastric nerve will be brought into view. It lies behind and 
between these great vessels, and in the same sheath. It may 
be traced downwards over the subclavian arterj^, where it 
gives off the inferior laryngeal hranchj which winds round the 



SUPEEFICIAL PAETS OF THE NECK. 



169 



posterior surface of the subclavian artery to ascend to tlie 
larynx. 

Fig. 65. 




30 29 



A View of the Arteries op the Neck and Shoulder. — 1. Primitive carotid 
artery. 2. Internal carotid artery. 3. External carotid artery, i. The superior 
thyroid arterj^ 5. Branches to the muscles. 6. Main branch to the gland. 7. In- 
ferior pharyngeal artery. 8. Lingual artery. 9. Facial artery. 10. Its branches 
to the submaxillary gland. 11. Submental branch. 12. Principal branch of the 
facial as it goes over the jaw. 13. Occipital artery. 14. Branches to the muscles 
on the back of the neck. 15. Main trunk to the occiput. 16. Posterior auricular 
artery. 17. A branch cut off, which goes to the parotid gland. IS. Origin of the 
internal maxillary artery. 10. Origin of the temporal artery. 20. Origin of the 
anterior auricular. 21. The subclavian. 22. Origin of the internal mammary. 
23. Trunk of the inferior thyroid, from which arise in this subject the anterior and 
posterior cervical arteries. 24. Branch of the inferior thyroid going to the thyroid 
gland. 25. Ascendcns colli going up the neck. 26. Posterior or transverse cervical. 
27. Branches to the scaleni and levator scapuliv) muscles. 2S. The supra-scapular 
artery. 29. The thoracica acromialis of the axillary artery. 30. A branch to the 
deltoid. 31. Recurrent branches of the intercostals. 

Tliis brancli of tlic pnciunogastvic may bo traced from its 
origin to its cntranco into the larynx. Ijeaving the artery 
and proceeding a short distance obliquely inwiuxls and up- 
15 



170 DISSECTION OF THE NECK. 

wards, it gets into tlie groove formed by the trachea and 
oesophagus, and continues in this groove to the lower border 
of the inferior constrictor muscle of the pharynx, to which it 
gives some filaments ; it then passes round outside the crico- 
thyroid articulation, to divide into branches to supply all 
the muscles of the larynx except the crico-thyroid. While 
in connection with the subclavian artery, it gives off branches 
to join the cardiac branches of the sympathetic. It also, in 
its course, sends filaments to the trachea, oesophagus, and 
thyroid gland. The situation of this nerve is to be noticed as 
connected with oesophagotomy. 

About an inch and a half from the bifurcation of the 
arteria innominata, the inferior thyroid artery passes trans- 
versely beneath the common carotid, the internal jugular, 
and the pneumogastric nerve. The course of this artery 
should be observed as connected with the ligation of the 
carotid, and also with oesophagotomy. 

The dissection is now to be extended along the course of 
the Subclavian Artery, Fig 65 (21). This artery, from 
its relations to the scalenus anticus muscle, is divided into 
three sections : the first extends from its commencement to 
the inner border of the scalenus; the second includes that 
portion directly behind the muscle, and the third division ex- 
tends from the outer border of this muscle to the point where 
it passes over the first rib to terminate in the axillary artery. 

The deep cervical fascia in this region is quite thick and 
dense. It is firmly attached to the clavicle and first rib. 
The vessels and nerves, and the scalenus anticus, obtain 
investments from it. A prolongation is also sent down from 
it into the thorax, along with the trachea and the large vessels 
and nerves which enter that cavity from the neck. The dis- 
section of this region is somewhat difficult. The parts will be 
noticed in the order in which they seem most naturally to 
present themselves to the dissector. The internal jugular 
vein and the pneumogastric nerve may be divided some 
distance above the subclavian artery, and reflected down- 
wards. Filaments of the sympathetic may be noticed passing 
over the artery to enter the thorax. 

The Branches of the subclavian artery are numerous, 
and, with the exception of one, have their origin on the inner 
side of the scalenus. The thyroid axis^ as it is called, is some- 
times the common origin of the inferior thyroid, the supra- 



SUPERFICIAL PARTS OF THE NECK. 



171 



scapular, and the transverse linmeral. As these branches, 
so frequently arise separately, although near to each other, 
the term "• thyroid axis" might very properly be abandoned. 

Fig. 66. 




A View of the Heart, avith the Great Vessels op the Neck in Sitit. — 1. 
Kight ventricle of the heart. 2. Right auricle. 3. Left ventricle. 4. Left auricle. 
6. Pulmonary artery. 6. Arch of the aorta. 7. Descending vena cava at its 
entrance into the right auricle. 8. Ascending vena cava. 9. Thoracic aorta. 10. 
Arteria innominata. 11. Right brachio-cephalic vein. 12. Left brachio-cephalic 
vein. 13. Section of the subclavian artery. 14. Section of the subclavian vein. 
15,15. Primitive carotid arteries. 16,16. Internal jugular veins. 17, 17. External 
jugular veins. Between these veins is seen the section of the sterno-cloido-mastoid 
muscle. 18. The trunk formed by the suporlicial cervical veins, known sometimes 
as the anterior jugular vein. 19. A branch from it to the facial. 20. Main trunk 
from the inferior thyroid veins. 21. Superior thyroid vein. 22. Transverse cer- 
vical artery and vein. 23. Lingual artery and vein. 24. Facial artery and vein. 

The Inferior Thyroid, Fig. 65 {23), comes oft' from the 
anterior and upper aspect of the artery, a short distance 
from the scalenus; it passes upwards about an inch, Avhen it 



172 ." DISSECTION OF THE NECK. 

turns inwards and dips beneath, the jugular vein, common 
carotid artery, and pneumogastric nerve, to go to the thyroid 
gland, to whiclL the greater part of it is distributed. It sends 
small branches to the oesophagus, the trachea, and to tlie 
larynx. The middle cervical ganglion of the sympathetic, 
when it exists, rests upon it. 

The AscEXDEXS Colli, Fig. 65 (2 5), is usually a branch 
of the thyroid ; the point of its origin, liowever, varies ; some- 
times it comes off as the thyroid turns inwards, and if it be 
large, causes the appearance of a bifurcation of that artery. 
It ascends apon the scalenus anticus on the neck, giving 
branches to this muscle and to the rectus capitis anticus major, 
and the levator anguli scapulae. It also gives off branches to 
anastomose with the vertebral artery, and to enter the spinal 
canal along with, the cervical nerves. 

The SuPEA-scAPULAE Aeteet, Fig. 65 (2 s), passes trans- 
versely outwards, just behind the clavicle, to reach the cora- 
coid notch ; it does not usually pass through the notch, but 
immediately over the ligament which converts it into a fora- 
men. It is situated beneath the deep fascia, and in its course 
gives off a small branch which enters the thorax. On the 
dorsum of the scapula it anastomoses beneath the acromion 
with the arteria dorsalis scapulae. 

The Teansveese Hu^ieeal, or Ceevical, Fig. 65 {26), 
passes transversely outwards, but above the preceding, to the 
trapezius. It is distributed to the muscles on the back of 
the neck, and anastomoses with the arteria princeps cervicis, 
a branch of the occipital artery. Both of the last named 
arteries are to be studied in their relations to the operation 
for ligating the subclavian artery. 

The Inteenal Mammaey Aeteet, Fig. 66 (22), arises 
from the lower surface of the subclavian, and very soon 
enters the thorax. It passes beneath, the clavicle, the sub- 
clavian vein, and the phrenic nerve, before it gets behind the 
first rib. Its course in the thorax, and in the anterior walls 
of the abdomen, will be noticed in the dissection of those 
parts. It may be mentioned now that it anastomoses with 
several arteries, as the superior thoracic, the intercostal, 
and the epigastric. These anastomotic connections render 
its study important. 



SUPEEFICIAL PAETS OF THE NECK. 
Fig. 67. 



17a 




The course and distribution op the Hypoglossal or Ninth Pair of Nerves. 
The deep-seated Nerves of the Neck are also seen. — 1. The hypoglossal 
nerve. 2. Branches communicating with the gustatory nerve. 3. A branch to the 
origin of the hyoid muscles. 4. The descendens noni nerve. 5. The loop formed 
with the branch from the cervical nerves. 6, 6. Muscular branches to the depressor 
muscles of the larynx. 7. A filament from the second cervical nerve, and 8. A 
filament from the third cervical, uniting to form the communicating branch with 
*he loop from the descendens noni. 9. The auricular nerve. 10. The inferior 
dental nerve. 11. Its mylo-hyoidean branch. 12. The gustatory nerve. 13. The 
chorda tympani passing to the gustatory nerve. 14. The chorda tympani leaving 
the gustatory nerve to join the submaxillary ganglion. 15. The submaxillary 
ganglion. 16. Filaments of communication with the lingual nerve. 17. The 
glosso-pharyngeal nerve. 18. The par vagum or pneumogastric nerve. 19, The 
three upper cervical nerves, 20. The four inferior cervical nerves. 21. The first 
dorsal nerve. 22, 23. The brachial plexus. 24, 25. The phrenic nerve. 26. The 
carotid artery. 27. The internal jugular vein. 

The Yertebral Artery, Fig. 68 (7), is tlie largest brancli 
of the subclavian. It arises from the upper and posterior 
part of that artery, and passes directly up to the foramen 
in the transverse process of the sixth cervical vertebra, 
which it traverses, and also the corrcs})onding foramina of the 
upper five vertebra) ; it enters the cranial cavity through the 
foramen occipitale, to be distributed to the brain and its me- 
ninges. In its course along the neck it sends branches to 
the spinal canal, and gives oft' also some small muscular 
twigs. It varies in its origin in dilfereut subjects, and ou 

15^ 



174 



DISSECTION OF THE NECK. 




Fig- G8. tlie two sides in tlie same 

subject; also in the num- 
ber of transverse processes 
through which it passes. 

From the posterior part 
of the subclavian two 
branches arise, sometimes 
separately and sometimes 
by a common trunk— the 
superior intercostal and 
the profound cervical. 

The SuPEKioR Inter- 
costal passes over the 
neck of the first rib and 
enters the superior inter- 
costal space ; on the right 
side, it very frequently sup- 
plies the upper two inter- 
costal spaces. 

The Profound Cervi- 
cal passes backwards be- 
tween the transverse pro- 
cess of the seventh cervical 
vertebra and the first rib. 
It assists in supplying the 
deep muscles on the back. 

The small veins in this region correspond to the branches of 

the subclavian artery. 

The Phrenic Nerve, Fig. 67 (24), arises from the third 
and fourth cervical, and passes obliquely downwards and in- 
wards over the scalenus anticus to enter the thorax. The 
subclavian vein lies in front of it, and the internal mammary 
artery behind it. It communicates usually by one or two 
filaments with the descendens noni ; it is also generally con- 
nected by a branch of considerable size with the fifth cervical 
nerve. As it crosses the scalenus it is bound down by fascia. 

The Subclavian Yein, Fig. %Q (14), extends from the 
sterno-clavicular articulation to the first rib, on the inner side 
of the scalenus anticus, which separates it from the subclavian 
artery. It is more superficial than the artery, and on a plane 



a View of the Vertebral Artery, 
Carotid axd Arch of the Aorta, as giyen 
BY A Vertical Section of the Neck. — 1. 
Commencement of the thoracic aorta, 2. 
The innominata at its origin. 3. The left 
subclavian. 4. The internal mammary 
artery. 5. The artery of the right side. 
6. The inferior thyroid. 7. The vertebral 
in the transverse processes of the cervical 
vertebrae. 8. Superior intercostal artery. 
9. Left primitive carotid. 10. External 
carotid artery. 11. Superior thyroid. 12. 
The lingual, Tivhich has here a common 
trunk Tvith the facial. 13. Internal carotid. 
14. Origin of the aorta. 



SUPEEFICIAL PAETS OF THE NECK. 175 

lower down. It receives the external jugular, wliicli usually 
enters it a little on the outside of the scalenus, or in front of 
it. The external jugular occasionally terminates in the inter- 
nal jugular. The veins corresponding to the supra-scapular 
and transverse humeral arteries enter the subclavian. 

The Scalenus Anticus Muscle, Fig. 71 (2), arises from 
the transverse processes of the third, fourth, fifth, and sixth 
cervical vertebrae, and is inserted in a tubercle on the first rib. 
It draws the first rib up, or turns the head to one side. 
This muscle and the tubercle which indicates the point of its 
insertion furnish important guides for finding the subclavian 
artery, and, on this account, they demand the special atten- 
tion of the student. This muscle may now be detached from 
the rib and turned upwards, when the middle division of the 
subclavian artery is brought into view. It is in relation with 
the pleura, first rib, the lower cervical and first dorsal nerves, 
and the anterior and middle scaleni muscles. 

The Posterior Cervical Artery usually arises from the 
outer portion of this division. This artery passes transversely 
outwards to be distributed to the muscles on the back ; some- 
times it is a branch of the transverse humeral. It is liable 
to be injured in ligating the subclavian artery between the 
scalenus anticus and the first rib. 

Outside the scalenus anticus is the SuprA-SCAPular 
Nerve, which arises from the fifth cervical and passes doAvn- 
wards and backwards, beneath the trapezius and omo-hy- 
oideus, to reach the coracoid notch of the scapula. It enters 
the supra-spinata fossa, and is distributed to the parts on the 
dorsum of the scapula. 

The third division of the subclavian artery and the nerves 
which form the brachial plexus are in this region. The 
artery passes over the first rib to terminate in the axillary. 
The nerves lie partly behind and above it, but in close rela- 
tion to it. The scalenus mcdius is sometimes perforated by 
one or more of them. The superior and long thoracic 
branches generally have their origin from these nerves above 
the clavicle. 

The Scalenus, Mepius and Posticus, may be considered 
as a single muscle which arises from the transverse processes 
of the inferior six cervical vertebrae, and is inserted into the 
first and second ribs. 



176 DISSECTION OF THE NECK. 

The upper part of tlie superior carotid and the submaxil- 
lary regions will be described separately, as far as the student 
will be able to dissect conveniently the parts which they 
contain, without destroying or displacing too much their 
boundaries. Some parts will be partly brought into view 
and noticed without their being fully dissected and exposed 
until a more advanced stage of the dissection ; and some 
which are deep-seated can be dissected better without refer- 
ence to regions, as the deep muscles, the sympathetic, and 
the nerves generally in the upper and deep part of the neck, 
consequently these will be described under the head of the 
deeji parts of the neck. 

The submaxillary region contains the Submaxillary 
Gland, Fig. 8(3), which should be dissected first, on account 
of its size and the important relations which it sustains to 
the vessels and nerves of that region. This gland is covered 
by a layer of the deep fascia in which it is embedded. It is 
of an irregular shape ; the transverse diameter being somewhat 
greater than the vertical. In structure, it resembles the other 
salivary glands. Anteriorly, it projects over the mylo- 
hyoideus, and sends a prolongation beneath it ; below, it is 
in relation with the digastric and stylo-hyoid muscles ; pos- 
teriorly, it rests against the process of the deep fascia which 
is attached to the stylo-hyoid ligament ; above, it occupies a 
fossa on the inner surface of the lower jaw. There are seve- 
ral lymphatic glands situated in this region around the sub- 
maxillary gland. They receive lymphatics from the mouth, 
face, and pharynx ; hence they are liable to become affected 
in cases of disease located in either of these regions. An 
enlarged lymphatic gland, in the immediate vicinity of the 
submaxillary, might be mistaken for disease of the submax- 
illary gland itself 

In dissecting this gland, the following parts will be brought 
into view : — 

The Facial Arteey, Fig. 65 (9), passes beneath its posterior 
extremity, occupying a sulcus in its substance, and sending 
branches to it. The submental branch (11) of the same artery 
gives small branches to the gland, and passes forwards over 
the mylo-hyoideus to near the symphysis of the chin, where, 
after giving branches to the parts beneath the chin, it goes 
up over the jaw to the face. The facial artery usually gives 



SUPERFICIAL PARTS OF TEE NECK. 177 

off two or three other small branclies in this region, one to 
the pterygoidens internus, and another to the soft palate. 

The Hypoglossal Nerve, Fig. 67 (i), enters the anterior 
and lower part of the submaxillary region from beneath the 
digastricus and stylo -hy oldens ; runs a short distance before 
it gets on the anterior surface of the hyo-glossus, just above 
the greater cornu of the hyoid bone ; it then passes upwards 
and forwards between the hyo-glossus and mylo-hyoideus to 
reach the tongue. In its course through this region it gives 
off branches to the thyro-hyoideus, stylo -glossus, and hyo- 
glossus, and to anastomose with the gustatory branch of the 
fifth nerve. 

The Gustatory or Lingual Branch, Fig. 67 (12), of the 
fifth enters this region at the anterior border of the ptery- 
goideus internus, and partly behind the gland. This nerve 
is brought into view by separating the gland from the lower 
jaw, and loosening it up from the hyo-glossus. It passes 
over the hyo-glossus and along the stylo-glossus muscle, in 
nearly a transverse direction, to the genio-hyo-glossus, which 
it perforates, to go to the sublingual gland and mucous mem- 
brane of the mouth. With a very little care in exposing this 
nerve, the submaxillary ganglion may be observed connected 
to its lower border, and situated nearly opposite the centre 
of the submaxillary gland. From this ganglion filaments 
are sent to the substance of the gland, and to the duct of 
Wharton, and mucous membrane of the mouth. The gan- 
glion is quite small, of a grayish color, and often appears 
like a slight projection from the nerve. It is classed with 
the cranial ganglia of the sympathetic. The vidian nerve is 
said to terminate in it after accompanying for some distance 
the gustatory. 

The Mylo-IIyoid branch of the inferior dental nerve enters 
this region above the gland, and close to the inner surface of 
the jaw, and gets on the cutaneous surface of the m3do-h3'oi- 
deus, to which, and the digastricus, it sends filaments, and 
also to the gland. 

The anterior belly of the digastricus may now be detached 
from the lower jaw, and reflected downwards without destroy- 
ing its attachment to the hyoid bone. The insertion of the 
stylo-hyoideus may also be observed at the same time. Ko- 
moving the areolar tissue, mylo-hyoid nerve, submental 



178: 



DISSECTION OF THE NECK. 



artery and vein, and tlie anterior projection of tlie gland, 
from the cutaneous surface of the mylo-hyoideus, the origin 
and insertion of this muscle will be exposed. 

The Mylg-Hyoideus, Fig. 69 (5), is a broad mnscle, and 
from its important relations deserves special notice. It arises 

Fig. 69. 




The Muscles of the Anterior Aspect op the Neck ; on the left side the 
Superficial Muscles are seen, and on the right the Deep. — 1. The posterior 
belly of the digastricus muscle. 2. Its anterior belly. The aponeurotic pulley, 
through which its tendon is seen passing, is attached to the body of the os hyoides. 
3, 4. The stylo-hyoideus muscle, transfixed by the posterior belly of the digastricus. 
6. The mylo-hyoideus. 6. The genio-hyoideus. 7. The tongue. 8. The hyo- 
glossus. 9. The stylo-glossus. 10, The stylo-pharyngeus. 11. The sterno-mastoid 
muscle. 12. Its sternal origin. 13. Its clavicular origin. 14, The sterno-hyoid. 
35. The sterno-thyroid of the right side, 16. The thyro-hyoid, 17. The hyoid 
portion of the omo-hyoid. 18, 18. Scapular portions ; on the left side, the tendon 
of the muscle is seen to be bound down by a portion of the deep cervical fascia. 
19. The clavicular portion of the trapezius. 20. The scalenus anticus of the right 
side. 21. The scalenus posticus. 

from the mylo-hyoid ridge, on the inner surface of the 
lower jaw ; its fibres pass downwards, forwards, and inwards, 
to be inserted into the hyoid bone, and to join its fellow on 
the opposite side along the median line. This muscle may 
draw up the hyoid bone, or, when it is fixed, may depress 
the lower jaw. A small triangular space, occupied by areo- 
lar tissue, exists between the two mylo-hyoid muscles just 



SUPEEFICIAL PARTS OF THE NECK. 179 

below the symphysis of the chin. This muscle should be 
carefully detached from the mylo-hyoid ridge, and from the 
hyoid bone, and reflected to the opposite side, when the 
hypoglossal and gustatory nerves^ and the duct of Wharton will 
be seen resting on the hyo-glossus. The duct, for a short 
distance after leaving the gland, is situated between these 
nerves, but nearer to the gustatory than the hypoglossal, 
which crosses it. 

The Duct of Whaeton is nearly two inches in length ; 
its walls are very thin in proportion to its caliber. It leaves 
the hyo-glossus, and gets at first between the genio-hyo- 
glossus and the sublingual gland, then between the gland and 
the mucous membrane, between which it continues to the frse- 
num of the tongue, just behind the incisor teeth. The student 
will have no dif&tjulty in tracing this duct, if an incision be 
made into it near its origin, and a bristle introduced and 
carried through it into the mouth. Its proximity to the 
cavity of the mouth, in the latter part of its course, and the 
distensible character of its parietes, deserve notice, with refe- 
rence to ranula, or an enlargement of the duct from closure 
of its buccal orifice. 

The Genio-Hyoideus, Fig. 69 (e), is a small muscle which 
arises from the lower jaw, near the symphysis, and passes 
downwards and backwards, and is inserted into the hyoid bone. 
The two genio-hyoidei muscles are frequently so closely con- 
nected along the median line that it is not easy to separate 
them. The action of this muscle is nearly the same as that 
of the preceding one. After detaching this muscle from its 
origin, and reflecting it downwards, the anterior border of 
the genio-hyo-glossus will be seen. The genio-hyoid part of 
it may now be observed, but its connection with the tongue 
must be examined when that organ is dissected. The sub- 
maxillary gland may next be removed entirely, when the 
hyo-glossus, the stylo-glossus, the stylo-pharyngeus, the lin- 
gual artery, and the sublingual gland, with a portion of the 
mucous membrane of the mouth, will be brought into view. 

The Stylo-Glossus, Fig. 70 (3), arises from the styloid 
process and stylo- maxillary ligament, passes downwards and 
forwards to be lost principally in the side of the tongue. 
As it enters this organ its fibres spread out, and a few of 



180 



DISSECTION OF THE NECK. 



tliem pass transversely across it It acts on tlae sides and 
tip of tlie tongue. 

Fig. 70. 




The Anatomy of the side of the neck, showing the nerves of the Tongue. 
— 1. A fragment of the temporal bone containing the meatus auditorius externus, 
mastoid, and styloid processes. 2. The stylo-hyoid muscle. 3. The stylo-glossus, 4. 
The stylo-pharyngeus. 5. The tongue. 6. The hyo-glossus muscle ; its two por- 
tions. 7. The genio-hyo-glossus muscle. 8. The genio-hyoideus ; they both arise 
from the inner surface of the symphysis of the lower jaw. 9. The sterno-hyoid 
muscle. 10. The sterno-thyroid. 11. The thyro-hyoid, upon which the thyro- 
hyoidean branch of the hypoglossal nerve is seen ramifying. 12. The omo-hyoid 
crossing the common carotid artery (13), and internal jugular vein (14). 15. The 
external carotid giving off its branches. 16. The internal carotid. 17. The gusta- 
tory nerve giving off a branch to the submaxillary ganglion (18), and communi- 
cating a little further on with the hypoglossal nerve. 19. The submaxillary, or 
Wharton's duct, passing forwards to the sublingual gland. 20. The glosso-pharyn- 
geal nerve, passing in behind the hyo-glossus muscle. 21. The hypoglossal nerve 
curving around the occipital artery. 22. The descendens noni nerve, forming a 
loop with (23) the communicans noni, which is seen to be arising by filaments from 
the upper cervical nerves. 24. The pneumogastric nerve, emerging from between 
the internal jugular vein and common carotid artery, and entering the chest. 23. 
The facial nerve, emerging from the stylo-mastoid foramen, and crossing the exter- 
nal carotid artery. 



The Hyg-G-lgssus, Fig. 70 (e), is a thin square mnscle, 
which arises from the body and great cornu of the hyoid 
bone; its fibres pass upwards and are inserted into the tongue, 



SUPEEFICIAL PAETS OF THE NECK. 181 

between the stylo-glossus, witli which its fibres intermix, and 
the lingnalis. 

The Lingual Artery, Eig. 65 (s), enters the submaxillary 
region a short distance outside the free extremity of the great 
cornu of the hyoid bone, and on a plane somewhat deeper. 
It almost immediately passes behind the hyo-glossus muscle, 
just above the cornu of the hyoid bone, to get between 
the genio-hyo-glossus and lingualis. The middle constrictor 
of the pharynx lies behind it, in the first part of its course. 
The situation and relations of this artery should be noticed 
with reference to the application of a ligature to it. 

The Stylo-Pharyngeus Muscle, Fig. 70 (4), arises from 
the styloid process, passes downwards and inwards to the 
pharynx, which it enters between the superior and middle 
constrictors. The glosso-j)liaryngeal nerve runs along the 
side of this muscle between it and the stylo-glossus to the 
margin of the hyo-glossus, beneath which it passes to the 
base of the tongue, sending filaments in this region to the 
pharyngeal plexus. The dissector will find the stylo-pharyn- 
geus muscle a guide for finding this nerve. 

The Sublingual Gland, Fig. 3 (5), is the smallest of the 
three large salivary glands. It is situated near the symphy- 
sis of the chin, occupying a fossa on the inner side of the 
lower jaw. Its upper surface is covered by the mucous 
membrane of the mouth, between the incisor teeth and the 
tongue ; below, it rests upon the mylo-hyoideus muscle ; ante- 
riorly, it is in relation with the lower jaw. It is somethiies 
connected by a process with the submaxillary gland. Its 
excretory ducts are ten or twelve in number. They open into 
the mouth near the fr^num of the tongue. Sometimes they 
are called the ducts of Rivinus. A communication occasion- 
alty exists between these ducts and the duct of Wharton. 

The relations of the submaxillary and sublingual glands 
are worthy of particular notice. It will be observed that the 
su.bmaxillary is covered externally by skin, superficial fascia, 
platysma myoides, and deep fascia, while the sublingual is 
covered internally by mucous membrane, and submucous 
areolar tissue. The mylo-hyoideus forms the principal sep- 
tum between them. They are both in apposition with the 
lower jaw; the sublingual occupying the sublingual fossa, 
IG 



182 DISSECTION OF THE NECK. 

and the submaxillary tlie submaxillary fossa, wliile tlie two 
fossae are separated by the mylo-hyoid ridge. 

In dissecting the upper part of the superior carotid region, 
the first thing which should be sought is the hypoglossal 
nerve. This enters it beneath the posterior belly of the di- 
gastricus, at a point almost directly below the angle of the 
lower jaw, passes downwards, forwards, and upwards, to enter 
the submaxillary region near the free end of the great cornu 
of the hyoid bone. It thus forms a cu.rve in this region, the 
convexity of which looks downwards. The lowest part of 
this curve is about three-fourths of an inch below the digas- 
tricus. As it descends beneath the digastricus, it gives off 
the descendens noni. 

The Descenders Noni, Fig. 67, (4, 5), passes vertically 
downwards, receiving one or two branches from the second 
cervical nerve, or cervical plexus, by which a hop is formed ; 
from the convexity of this loop, filaments are sent to the omo- 
hyoideus and sterno-hyoideus and thyroideus. The apparent 
origin of this varies in different subjects. Sometimes it seems 
to come from the pneumogastric, occupying, in this case, for 
a short distance, the groove behind and between the common 
carotid and internal jugular vein; again, it will be found 
leaving the hypoglossal high up in the parotid region. 

If there be any difficulty in finding the nerve in the upper 
part of this region, it is better either to find one of its branches 
and trace it upwards, or to trace the hypoglossal nerve itself 
up into the parotid region. In this way the student will be 
certain to find it. The descendens noni usually, near its com- 
mencement, winds round the occipital artery. As this nerve 
lies on the sheath of the common carotid, it is liable to be 
injured in ligating that artery. 

The Spinal Accessory Nerve passes through the upper 
and posterior part of this region, to perforate the sterno-cleido- 
mastoideus. It is is most readily found by carefully dissect- 
ing the inner and posterior surface of that muscle, and look- 
ing for the nerve as it enters it. Occasionally, the nerve 
passes beneath the muscle. 

The superior laryngeal branch of the pneumogastric miay be 
found with the laryngeal branch of the superior thyroid ar- 
tery, between the hyoid bone and the thyroid cartilage. They 
pass beneath the thyro-hyoid muscle, to perforate the thyro- 



SUPERFICIAL PARTS OF THE ITECK. 183 

hyoid membrane. This nerve can be exposed more con- 
veniently at another stage of the dissection of the neck. 
Having found this portion of it, the student may avoid 
destroying it as he proceeds. 

As the lower part of the inferior carotid region has already 
been dissected, the student will have no difficulty in tracing 
the arteries in its upper part. The common carotid usually 
bifurcates at a point nearly opposite to the superior border 
of the thyroid cartilage. The external is at first more internal 
than the internal carotid itself. It gives off' the following 
branches before passing beneath the digastricus :■— 

The Superior Thyroid, Fig. 65 (4), arises near the bifur- 
cation, passes inwards, forwards, and downwards, beneath the 
omo-hyoideus and sterno-thyroideus, to be distributed to the 
upper and anterior portion of the thyroid gland. It usually 
gives off the laryngeal branchy which goes to the thyro-hyoid 
space to enter the larynx ; the cricoid branchy which rests on 
the anterior crico-thyroid ligament; a branch to the sterno- 
cleido-mastoideus ; and branches to the muscles w^ith which 
it is connected. This artery is quite superficial in its course. 

The lingual arises just above the preceding, and passes up- 
vfards and inwards to enter the submaxillary region. It is 
deep-seated in its whole cou.rse. 

^h.Q facial artery comes off* just below the digastric muscle, 
and goes up into the submaxillary region. 

The inferior or ascending pharyngeal arises near the bifur- 
cation and from the deep part of the artery, and goes upwards 
to the jugular foramen, through which it enters the cavity of 
the cranium, sending branches, as it ascends, to the pharynx 
and soft palate. 

The Occipital, Fig. 65 (1 3), arises from the posterior part 
of the artery, passes upwards and backwards, at first behind 
the digastricus, and then more horizontally beneath the sterno- 
cleido-mastoideus, trachelo-mastoideus, and splenius capitis, to 
reach the occiput. It emerges beneath the integument and 
fascia, just outside the cranial origin of the trapezius. It 
gives off branches to the muscles along its course, and, just 
before it ascends on the occiput, it sends downwards quite a 
large branch, called the artcria prince^is cervicis; this branch 
descends on the back of the neck, and anastomoses with the 
transverse humeral. The occipital artery ramifies on the 
back of the head, beneath the skin. 



184 DISSECTIO^' OF THE NECK. 

The PosTEEiOE AupjcrLAE, Pig. 65 (le). arises above, or 
in common with, the occipital, and passes upwards and back- 
wards between the mastoid process and meatus auditorius. 
It ramifies on the external ear, and beneath the integument 
behind the ear. 

The styloid is more frequently a branch of the posterior 
auricular ; it enters the foramen stylo-mastoideum, and goes 
to the middle ear. 

Besides the branches just mentioned, the external carotid 
generallv sends two or three small ones to the sterno-cleido- 
mastoideus. 



Sect. II. — Dissection of the deep paets of the Xeck. 

The examination of these parts requires a displacement of 
the lower jaw. or at least the half on the side upon which 
they are to be dissected. The only additional section which 
will be required will be through the symphysis of the chin, 
when the remaining portions of the jaw upon that side may 
be drawn upwiirds and forwards, out of the way, or they 
may be entirely removed. 

The parts to be examined in the present dissection are the 
internal carotid artery, the internal jugular vein, the pneumo- 
gastric. the giosso -pharyngeal, the spinal accessory, the hypo- 
glossal, and the sympathetic nerves, and the pharyngeal plexus, 
and some of the deep muscles of the neck. Most of the parts 
just enumerated have been examined as they were found in 
the different regions already dissected. The following de- 
scription, therefore, will be confined principally to those por- 
tions of them which remain to be exposed. 

The branches of the external carotid may be cut away, as 
the dissector shall find it necessary, in the progress of the 
dissection. The digastricus and the stylo-hyoideus may be 
divided near their hyoid attachments, and reflected backwards. 

The IxTEEXAL CaeotiD; Fig. 65 (2), passes upwards nearly 
in a vertical direction from the bifurcation of the common 
carotid, to the foramen caroticum in the petrous portion of 
the temporal bone, through which it enters the cranial cavity. 
In the superior carotid region, it is quite superficial, being- 
covered merely by the integument, platysma myoides, and 



DEEP PARTS OF THE NECK. 185 

tlie superficial and deep fascise; bnt, as it ascends, it gradu- 
ally becomes deeper seated. Its size is not varied in this 
part of its course. 

Below the digastricus, the hypoglossal nerve and the occip- 
ital artery cross it in front, while the external carotid lies 
on the inner side of it. Above the digastricus, and in the 
parotid region, it is crossed in front by the glosso-pharyngeal 
nerve and the stylo-glossus and stylo-pharyngeus muscles, 
rig. 67, which pass between it and the external carotid. It 
is also covered by the parotid gland, in which it is sometimes 
partially lodged. 

On its inner side are the pharynx and sympathetic nerve. 
Externally it is in relation with the internal jugular, the 
pneumogastric, the hypoglossal, and glosso-pharyngeal 
nerves. These nerves at first lie behind it, but soon get on 
the outside between it and the vein. The two latter, how- 
ever, do not continue in this connection down to the common 
carotid, but cross over in front of the artery, the one above, 
and the other below the digastricus, as before mentioned. 

Behind, it rests on the rectus capitis anticus major, separ- 
ated from it by fascia and by the pharyngeal and superior 
laryngeal branches of the pneumogastric, which pass inwards 
beneath it. 

The inferior or ascending pharyngeal artery runs at first 
on the inner side of the internal carotid, then behind it, up 
to the foramen lacerum posterius, or jugular foramen. The 
internal carotid is surrounded by a plexus of nerves. 

The relation of this artery to the pharynx is worthy of 
notice. It sustains nearly the same relation to the internal 
surface of the pharynx, as regards the intermediate structures, 
that it does to the external surface of the neck in the supe- 
rior carotid region. 

The Internal Jugular Yein, Fig. 67 (2 7), commences at 
the foramen lacerum posterius, and terminates by uniting 
with the subclavian to form the vena innominata. Near the 
foramen it is removed a short distance from the internal 
carotid, the intermediate space being occupied by nerves. 
There "is also a small space between it and the common 
carotid in the lower part of the neck. This vein is a con- 
tinuation of the lateral sinus ; it increases in size as it re- 
ceives collateral branches in its course down the neck. It 

16=^ 



186 DISSECTION OF THE NECK. 

presents two enlargements, one near its commencement, and 
the other just above its termination. It lias no valves. 

The GrLOSSO-PHAKYNGEAL Nerye, Fig. 67 (17), is a part 
of the eighth. It passes through the foramen lacerum pos- 
terius in a fibrous canal bj itself. It descends, at first be- 
tween the internal jugular and internal carotid, then in front 
of the artery and behind the styloid process and its muscles ; 
it now turns inwards, and passing in front of the stylo-pha- 
ryngeus, gets between it and the stylo-glossus ; continuing 
this course, it passes beneath the hyo-glossus, and enters the 
base of the tongue, to terminate in the papilla of the mucous 
membrane. 

There are two ganglia or gangliform swellings on this 
nerve; a small one in the foramen lacerum, and a larger 
one, the petrous or ganglion of Andersch, a little lower down. 
From the ganglion of Andersch proceed branches to anasto- 
mose with the sympathetic, the facial, the pneumogastric, 
and the nerves in the middle ear. The glosso-pharyngeal 
receives filaments from the spinal accessory, by which it be- 
comes partly a motor nerve in its distribution. Its muscu- 
lar branches are sent to the stylo -pharynge us, stylo-hyoideus, 
digastricus, hyo-glossus, and superior and middle constrictor 
muscles. The last-named muscles obtain their filaments 
through the medium of the pharyngeal plexus. Its sym- 
pathetic filaments go to the carotid plexus, and thus connect 
with the superior cervical ganglion. The tympanic branch, 
or Jacobson's, enters a small foramen betA^een the jugular 
foramen and foramen caroticum to go to the tympanum. This 
branch is noticed more particularly in connection with the 
ear. Its anastomotic branch to the facial winds round the 
styloid process, and joins that nerve just as it emerges from 
the stylo-mastoid foramen. It also sends filaments to the 
tonsils and palatine arches, forming the tonsillitic plexus. 

The Hypoglossal, or the ninth nerye, supplies the 
muscles of the tongue and larynx with voluntary motor fila- 
ments. It enters the neck through the anterior condyloid 
foramen ; just below which it is connected by filaments with 
the loop formed by the first and second cervical nerves, 
with the sympathetic by a small filament Y^hich comes from 
the superior cervical ganglion, and also with the pneumo- 



DEEP PAETS OF THE NECK. 187 

gastric. It anastomoses witli the gustatory brancli of tlie 
fifth in the submaxillary region, just before it passes beneath 
the mylo-hyoideus. The course of this nerve in the carotid 
and submaxillary regions, with the descendens noni and its 
other branches given off in these regions, has been described. 
In the parotid region it lies at first between the internal 
carotid and internal jugular, and behind the pneumogastric. 
"As it desceods, it gets on the outside of the pneumogastric, 
then in front of it, to turn inwards across the neck, and to- 
wards the tongue. 

The Spinal Accessoey leaves the cranial cavity with the 
glosso-pharyngeal and pneumogastric, passing through the 
foramen lacerum posterius with the latter. Just below the 
foramen it sends a large branch to join the pneumogastric, 
thus supplying this nerve with involuntary motor filaments. 
It also communicates with the sympathetic and ninth nerves. 
The main trunk descends, usually behind the jugular vein 
and the styloid muscles, to perforate the sterno-cleido-mas- 
toideus, or to send a branch to it, and then to pass on to the 
trapezius. Behind the sterno-cleido-mastoid it anastomoses 
with the cervical plexus. 

The Pneumogasteio, or Pae Yagum, is the largest divi- 
sion of the eighth nerve. It passes through the foramen 
lacerum posterius in the" same fibrous canal with the spinal 
accessory. There is a small ganglion situated on it in the 
foramen, and below the foramen it presents a gangliforni 
arrangement of about an inch in length. It here lies be- 
tween the carotid and the jugular vein. It gives off several 
communicating branches. From the superior ganglion fila- 
ments connect with the glosso-pharyngeal and spinal acces- 
sory; while from the inferior ganglion filaments communicate 
with the hypoglossal, the upper spinal, and the sympathetic 
nerves. 

The auricular branch of the pneumogastric leaves the su- 
perior ganglion, and after giving a small branch to Jacob- 
son's branch of the glosso-pharyngeal, enters the petrous 
portion of the temporal bone in the jugular fossa, and joins 
the focial nerve in its bony canal, sending filaments also to 
the integument around the meatus externus. 

The pharyngeal branch arises just below the foramen, 
sometimes receiving a branch from the spinal accessory, and 



188 DISSECTION OF THE NECK. 

occasionally from tlie glosso-pliaryngeal, and passes beneatTi 
the internal carotid to join, on the side of the pharynx, fila- 
ments from the glosso-pharyngeal, superior laryngeal, and 
superior cervical ganglion, to form the pharyngeal plexus. 

The superior laryngeal has its origin generally from the 
inferior ganglion near its middle. It is considerably larger 
than the preceding branch. It passes downwards and in- 
wards beneath the internal carotid, giving off in its course 
filaments to the superior cervical ganglion, to the hypo- 
glossal and pharyngeal plexus. It divides into an external 
and internal branch. The former is the smallest ; it is dis- 
tributed to the external muscles of the larynx, to the thy- 
roid gland, and anastomoses with the recurrent laryngeal, 
and cardiac branches of the sympathetic. The internal 
branch passes beneath the thyro-hyoid muscle, and per- 
forates the thyro-hyoid membrane, to be distribu.ted to the 
mucous membrane of the larynx. This is the sensor nerve 
of the larynx. 

The course of the pneumogastric nerve through the carotid 
regions and the recurrent branch, have already been de- 
scribed. Just before it enters the thorax it sends off branches 
to the heart ; they unite with branches of the sympathetic, 
to form the anterior cardiac plexus. 

The Sympathetic Neeve traverses the neck from the 
base of the cranium to the thorax. It presents three cervi- 
cal ganglia, a superior, middle, and inferior. The number, 
however, is subject to variation ; there being sometimes but 
two, and again there may be four. When three are present, 
the superior is situated in front of the second cervical ver- 
tebra ; the middle opposite to the fifth, and the inferior corre- 
sponds to the seventh vertebra. 

The superior ganglion is usually abou.t an inch in length ; 
its lower extremity is commonly larger than the upper, some- 
times it is bifid, and it may taper as it descends in the neck, 
below the second vertebra, which sometimes occurs. This 
ganglion connects above by filaments which ascend into the 
carotid canal, with the carotid plexus, and through this plexus 
with several of the cranial ganglia. Externally, it communi- 
cates with the four superior cervical nerves, by filaments which 
can be traced into the inter-vertebral foramina. Internally, 
it is connected by branches with the pharyngeal and laryn- 



DEEP PARTS OF THE NECK. 189 

geal brandies of the pneumogastric and the pharyngeal 
branches of the glosso-phar jngeal. The pharyngeal branches 
contribute to form the plexus which supplies the pharynx 
and fauces ; the laryngeal join the superior laryngeal nerve. 
Anteriorly, it gives off' branches to join the eighth and ninth 
nerves, and to go to the external carotid, from which fila- 
ments proceed to accompany its different branches. These 
filaments have been called, from their soft texture, " nervi 
mollesr 

The superior cardiac nerve arises from the inner side of the 
ganghon, by one or more filaments, descends behind the 
carotid and alongside of the trachea, and, passing in front of 
the inferior thyroid artery, enters the thorax in company 
with the arteria innominata. In its course down the neck it 
communicates with the pneumogastric and its laryngeal 
branches, also with the middle and inferior ganglia. 

The middle ganglion sends branches to one or two of the 
cervical nerves, and to the pneumogastric. The middle cardiac 
nerve arises from this ganglion when it is present. It pur- 
sues a course similar to the superior cardiac nerve. It com- 
municates with the recurrent laryngeal and superior cardiac. 

The inferior ganglion is dissected more satisfactorily in con- 
nection with the thoracic division of the sympathetic. The 
student must be prepared to meet with numerous variations 
in the arrangement of the sympathetic nerve. It is impos- 
sible to give a description of it which will correspond exactly 
with any two dissections. But a general knowledge of the 
numerous connections of this nerve is essential to a correct 
idea of its functions, and the influence it may exert in various 
pathological conditions of the body. 

The muscles which may now be examined, are the follow- 
ing:— 

The Eectus Anticus Major, Tig. 71 (i), arises from the 
transverse processes of the third, fourth, fifth, and sixth 
cervical vertebra?, passes upwards and is inserted into the 
cuneiform process of the occipital bone in front of the fora- 
men magnum. It presents a tendinous intersection, which 
gives attachment to many of its muscular fibres. 

Eectus Anticus Minor, Fig. 71 (t), arises from the trans- 
verse process of the atlas, and is inserted into the cunoiibrni 



190 



DISSECTION OF THE NECK. 



process of tlie occipital bone. It covers, in front, the articu- 
lation between the atlas and occiput. 

: The Kectus Capitis Late- 

Fig. 71. EALIS, Fig. 71 (i.o), arises from 

the transverse process of the 
atlas, and is inserted into the 
jugular eminence, on the occi- 
pital bone. It separates the 
jugular vein in front from the 
vertebral artery behind. The 
action of the recti muscles is to 
support the head, or to bend it 
slightly forwards or laterally. 

The LoNGUs Colli, Mg. 71 
(5, e), consists of three portions. 
The first arises from the central 
and anterior tubercle of the 
atlas, and passes down to be in- 
serted into the transverse pro- 
cesses of the third, fourth, and 
fifth cervical vertebrse. The 
second arises from the transverse 
processes of the third and fourth 
cervical vertebrae, and goes 
down to be attached to the 
bodies of the upper three dor- 
sal vertebrae. The third arises 
from the second and third cer- 
vical vertebrse, and passes down 
to be inserted into the bodies of 
the lower four cervical and 
upper three dorsal vertebrae. 
This muscle supports the ver- 
tebral column. 
From the experience acquired in the dissection of one side, 
the student will be able to go over the same ground the 
second time with more satisfaction to himself. If some things 
have escaped his attention, or he has failed to obtain a dis- 
tinct and correct view of them in his first dissection, he will 
have the opportunity of remedying these defects in his second. 
And he cannot acquire too great familiarity with any of the 




The Prevertebral Group of Mus- 
cles OF THE Neck. — 1. The rectus anti- 
cus major muscle. 2. The scalenus anti- 
cus. 3. Thelowerpart of the longus colli 
of the right side; it is concealed superi- 
orly by the rectus anticus major. 4. The 
rectus anticus minor. 5. The upper 
portion of the longus colli muscle. 6. 
Its lower portion; the figure rests upon 
the seventh cervical vertebra. 7. The 
scalenus medius. 8. Scalenus posticus. 
9. One of the intertransversales mus- 
cles. 10. The rectus lateralis of the 
left side. 



DEEP PAETS OF THE NECK. 191 

parts, even if lie should find it convenient to examine them 
repeatedly. His attention in the second dissection of the 
same parts should be directed more particularly to relational 
anatomy. The following are some of the points especially 
deserving of his notice: The operations of laryngotomy, 
tracheotomy, pharyngotomy, and oesophagotomy ; the parts 
to be cut through, and those to be avoided in these opera- 
tions ; also the parts which are liable to be divided in attempts 
to commit suicide by cutting the throat. 

The young physician is liable to be called upon to treat 
these wounds without being allowed time to consult his 
books, and consequently he should make himself thoroughly 
acquainted, when he has the opportunity, with the exact loca- 
tion and the relations of all the parts liable to be implicated 
in such injuries. The application of ligatures to the various 
arteries of the neck, and the anastomotic connections between 
them ; also the mianner in which the circulation w^ill be carried 
on when any particular artery is obliterated. The formation 
of tumors, and the effect they will be likely to have on the 
surrounding parts, whether those parts be vessels and nerves 
or the windpipe, the oesophagus, &c. 

In dissecting the left side, some peculiarities will be met 
with which do not occur on the right side. These are located 
in the lower part of the neck. They are introduced sepa- 
rately instead of alluding to them in connection with the de- 
scription of the right side, as it was thought this method 
would be less likely to cause embarrassment, especially to 
the beginner. 

The Left or Geeat Thoeacic Duct enters the neck be- 
hind and internal to the subclavian artery, opposite to the 
sixth or seventh cervical vertebra ; gets behind the internal 
jugular, and curves outwards, forwards, and downwards to 
open into the junction of the internal jugular and subclavian 
veins. If it be not injected, the student may have some 
difficulty in distinguishing it from the surrounding tissues. 
It is easily found, however, in the abdomen ; and, by insert- 
ing a blowpipe into it there, it may be filled with air, Avhcii 
it will swell up and bo readilj^ observed in the neck. It 
varies in its mode of termination ; sometimes it opens bv two 
trunks, one into the jugular and the other into the subcla- 
vian ; or it may open singly into either one of these veins. 



192 DISSECTIOIT OF THE NECK. 

It may divide into two trnnks in tlie thorax, and while one 
opens in the nsnal place on the left side, the other may open 
into the right subclavian along with the common lymphatic 
dnct of the right side. 

The SuBCLAYiAX Aeteet on the left side arises from the 
aorta, and consequently is longer than the one on the right 
side. The second and third divisions have the same relations 
as on the right side, but with the first or inner section it is 
quite difi'erent. Its direction is nearly vertical, and it 
makes, in passing behind the scalenus anticus, a much shorter 
turn. It is covered anteriorly by the same parts, although 
it is deeper seated. The pneumogastric does not pass over 
it, nor does. the inferior laryngeal or recurrent nerve wind 
around its posterior surface. It is also in relation with the 
thoracic duct. 

The Common Caeotid arises from the aorta, and therefore 
is longer than the right. It is nearer to the internal jugular 
and the oesophagus, and is also in relation to the thoracic 
duct. Its connections in the thorax will be mentioned when 
that cavity is examined. 

The Inteexal Jugulae Yeix on the left side requires no 
special notice. The pneumogastric nerve does not, as before 
mentioned, pass in front of the subclavian artery as on the 
right side ; nor does it give off the recurrent branch until it 
has reached the arch of the aorta. 

The oesophagus projects a little more on the left side than 
on the right, and hence it is ad\'ised that when it is necessary 
to open it that it should be done on this side. 



Sect. III. — Dissectiox of the Laeyxx. 

The larynx is situated in the upper and anterior part of 
the neck, in front of the pharynx and above the trachea. It 
presents a regular framework, which is composed of several 
fibro-cartilages joined together by ligaments. It is supplied 
with muscles, vessels, nerves, and mucous membrane. Its 
structure is such that it remains constantly patulous, while 
the mobility of its cartilages adapts it to the production of 
the voice. For the purposes of respiration merely, a very 



OF THE LARYKX. 193 

simple arrangement wonld have been sufficient, as in the 
case of the trachea and bronchial tubes. To make a thorough 
examination of this organ, the student should be provided 
with at least two larjnges ; one for the dissection of the 
cartilages and ligaments, and another for the muscles, ves- 
sels, and nerves. 

The Hyoid Bone should be examined before the dissec- 
tion of the. cartilages and ligaments of the larynx. It is 
situated between the base of the tongue and the upper part 
of the larynx, and is connected to both of these organs. It 
is named from its having a form resembling the Greek letter 
upsilon. Its position is nearly horizontal, being concave pos- 
teriorly and convex anteriorly. 

It consists of a central part or body, and four lateral por- 
tions called cornua. There are two cornua on each side, one 
large and one small. 

The Bodij^ Fig. 72 (i), is curved and flattened. It presents a 
superior anterior, and inferior posterior surface. The ante- 
rior superior surface is rough and 
uneven for the attachment of mus- ^^S- "2. 

cles. The inferior posterior surface 
is excavated, and sometimes occu- 
pied by a yellow areolar tissue. Its 
upper border gives attachment to 
the hyo-glossal membrane or sep- 
tum of the tongue. The thyro- 
hyoid muscle is inserted into its . . ,, 

. "^ (, . 1 T AnAnTERIOR ViEWOF THE Os 

mterior border. Hyoides.— l. The anterior con- 

The Great Cornua, Fig. 72 (2), vex side of the body. 2. The 

T T , 1 f> ji 1 cornu mains of the left Side. 3. 

proceed backwards from the ends The comu minus of the same 

of the body, and, diminishing in side. The comua were ossified 

size, terminate in tubercles. In the %^Zl"nJ "' '''" """"' '" '"'' 
young bone, they are connected to 

the body by cartilage. They present a superior and an in- 
ferior surface. 

The Small Cornua, Fig. 72 (3), arc two small bodies 
which project upwards from the junction of the bodv with 
the great coruua. The stylo-hyoid ligaments arc inserted 
into them. These ligaments are sometimes found ossified. 

The i)rincipal cartilages are the cricoid, the thvroid, the 
17 




194 



DISSECTION OF THE NECK. 



Fig. 73. 




two arytenoid, and the epiglottis. Besides tliese, tliere are 
four small bodies, two of which are named the appendices, 
and two the cuneiform bodies. 

The Ceicoid Cartilage, Tig. 73, is situated in the lower 
part of the larynx, and seems to belong partly to the larynx 
and partly to the trachea. It con- 
sists of a ring slightly elliptical, its 
transverse diameter being less than 
its antero-posterior. Its lower bor- 
der is horizontal, and corresponds to 
the first ring of the trachea. Its 
upper border is oblique from before 
backwards and upwards, making its 
vertical diameter about four times 
greater behind than before. It has 
four articular facets, two for the 
thyroid cartilage and one for each of 
the arytenoid. The former are situ- 
ated on its external surface, behind 
the centre and near the lower mar- 
gin. The latter are on its upper 
border behind, and about one-fourth 
of an inch apart; they are convex 
and sloping laterally, being adapted 
to the articular facets on the bases 
of the arytenoid cartilages. Its ante- 
ro-lateral surface is convex, and is principally occupied by 
the crico-thyroid muscle. On its posterior surface are ob- 
served two depressions, which give attachment to the crico- 
arj^tenoidei postici muscles. These depressions are separated 
by a vertical ridge, to which are attached some of the longi- 
tudinal muscular fibres of the oesophagus. Its internal sur- 
face is smooth and covered by mucous membrane. 

The Thyeoid Caetilage, Fig. 74, forms the upper, ante- 
rior, and lateral parts of the larynx. It consists of two plates 
or alse, which are joined at the median line in front, and 
separated behind nearly three-fourths of an inch. The angle 
formed by the junction of the al^ anteriorly is more promi- 
nent above than below, and more in the male than in the 
female. It forms what is called the "pomum Adami." On the 
external surface of each ala are two tubercles connected by 



a Front View of the Cri- 
coid Cartilage. — 1. Its in- 
ternal face. 2. The cavity of 
the larynx as formed by this 
cartilage. 3. Its inferior sur- 
face. 4, 4. The little heads 
or convesities for articulating 
with the arytenoids. 5, 5. The 
Surface of the superior edge for 
the attachment of the lateral 
crico-arytenoid muscles. 



OF THE LARYNX. 



195 




an oblique ridge. The lower tubercle is situated anteriorly 
and near the inferior border, Avhile the upper one is placed 
posteriorly and near the su- 
perior border. The surface Fig. 74. 
above and anterior to the 
oblique ridge is much larger 
than the one below and be- 
hind it. The latter is occu- 
pied by the sterno -thyroid, 
and the former by the thyro- 
hyoid muscle. The inferior 
border of each ala terminates 
behind in a projection down- 
wards, called the inferior or 
small cornu. It articulates 
with the cricoid cartilage. 
Just before the small cornu 
on each side is quite a deep 
notch; there is also another 
one, but not so deep in front. 
The upper border of each ala 
terminates posteriorly in a 
much longer projection, call- 
ed the superior or great cor- 
nu ; this is inclined backwards, and gives attachment to the 
lateral thyro-hyoid ligament. Anteriorly there is quite a 
deep notch, which can be distinctly felt in the living body. 
The posterior borders of the alas are thick and round for 
the attachment of the fibres of the inferior constrictor of 
the pharynx. 

The Arytenoid Cartilages, Figs. 75, 76, are situated 
behind, upon the cricoid, and between the alas of the thyroid. 
They are of a pyramidal form. The posterior surflice of each 
is concave, and occupied by the arytenoid muscle. The ante- 
rior surface is convex, with a slight elevation near the a}x\N: 
for the attaclimcnt of the superior vocal chord. The internal 
surface is flat and smooth. The base projects anteriorly 
nearly one-third of the way across the interior of the larynx, 
and gives insertion to the inferior vocal chord. It also pro- 
jects posteriorly and externally for the attachment of tlie 
crico-aryfccnoideus posticus muscle. The articular surface on 



A Lateral View of the Thyroid 
Cartilage.— 1. Its left half. 2. Its right 
half. 3. The superior margin. 4. The 
notch. 5. Anterior angle. 6. Inferior 
margin. 7. Posterior margin. 8, 8. Cor- 
nu majus of each side. 9. Cornu minus. 



196 



DISSECTION OF THE NECK. 



tlie base is concaA^e, and adapted to the corresponding articu- 
lar surface on the cricoid cartilage. The arytenoid cartilages 
belong essentially to the yocal chords, and as such should be 



Fig. 75. 





Ay Anterior View of the Left 
Arytenoid Cartilage. — 1. Its ante- 
rior face. The other references as in 
Fig. 76. 



A Posterior View of the Left 
.Arytenoid Cartilage. — 1. Its poste- 
rior face. 2. The sumtnit. 3. The 
base and cavity for articulating with 
the cricoid cartilage. 4. Its external 
angle. 5. Its internal angle. 



studied. They can be moved in an outward, inward, back- 
ward, and forward direction, and also allow to some extent 
of a spiral movement. By means of these 
Fig. 77. movements the vocal chords can be made 

tense or relaxed, and the size of the fissure 
between them, called the rima glottidis, can 
be increased or diminished in width. 

The Appendices are two small bodies 
surmounting the apices of the arytenoid 
cartilages. They are inclined backwards 
and towards each other, lengthening the 
curvature of these cartilages in this direc- 
tion, and at the same time increasing their 
vertical diameter. 




A Lateral View 
of the Epiglottis. — 
1. Anterior or convex 
surface. 2. Posterior 
or concave surface. 

3. Superior margin. 

4. Inferior margin or 
pedicle. 5, 5. Its 
sides. The openings 
of the muciparous 
ducts are also shown. 



The Epiglottis, Fig. 77, is generally 
spoken of as a fibro-cartilage, although its 
structure seems to be peculiar to itself. It 
is of an oval form. Its posterior surface is 
concave transversely, and convex vertically ; 
its anterior surface is just the reverse. The 
upper part of its anterior surface is free, 
and covered by mucous membrane, while 
the lower part is attached to the tongue, os 
hyoides, and thyroid cartilage. It is con- 



OF THE LAEYNX. 197 

nected to tlie tongue by yellow elastic tissue, to the body of 
the OS hyoides by ligamentous fibres, and also to the thyroid 
cartilage just above the anterior insertion of the vocal chords. 
Between the two latter attachments is found a mass of cellulo- 
adipose tissue, of a yellowish color, and surrounded by 
areolar tissue ; it has been called the "epiglottic gland," but 
without any good reason, as it is destitute of all the elements 
of a true gland. On the posterior surface of the epiglottis 
are observed numerous small foramina, orifices of mucous 
follicles. It is of a yellowish color, and very flexible and 
elastic, being easily depressed so as to meet the glottis in the 
ascent of the larynx, by the passage of food from the fauces 
into the pharynx, immediately recovering its vertical posi- 
tion when the pressure is removed. It is never found ossi- 
fied, like the other cartilages of the larynx. 

The cuneiform bodies are two small masses, found in the 
aryteno-epiglottidean folds of the mucous membrane, a short 
distance above the appendices or cornicula. Sometimes they 
are very indistinct, and possess very little firmness. 

The ligaments connecting the cartilages of the larynx to 
each other, and to the hyoid bone, are the following : — 

The thyroid cartilage is connected to the os hyoides by a 
middle and two lateral ligaments. 

The MIDDLE THYRO-HYOTD, Fig. 79 (4), is a broad, yellow 
ligament, extending from the centre of the upper border of 
the thyroid to the posterior part of the body of the os hy- 
oides. The LATERAL, Fig. 78 (4, 4), are round, fibrous cords, 
connecting the superior cornua of the tliyroid to the extre- 
mities of the great cornua of the os hyoides. The spaces 
between these ligaments are occupied by dense areolar tissue, 
The ligamentous attachments of the epiglottis have been 
spoken of in connection with that body, 

The cricoid cartilage is joined to the thyroid by three liga- 
ments, two lateral, and one middle, 

The LATERAL LIGAMENTS, Fig. 78 (9, 9), are regular capsular 
ligaments, containing, \\\ each, a synovial sac. Those articu- 
lations allow of a glidiqg and rotary movement. The :mtddle 
CRICO-THYROID, Fig, 79^ (10), is of the yellow elastic tissue, 
connecting the anterior part of the upper border of the cri- 
coid with the corresponding portion of the lower margin of 
the thyroid. It is perforated by one or more foramina, for 

17-^- 



198 



DISSECTION OF THE KECK. 



the transmission of vessels. It serves to keep the thyroid in 
its proper position, without interfering with its necessary 




Fig. 79. 




A Posterior View of the Artictt- 

LATIONS of the CARTILAGES OF THE LA- 

KYNX. — 1. Posterior face of the epiglot- 
tis. 2, 2. Appendices of the os hyoides. 
3, 3. Its cornua. 4, 4. Lateral thyro-hyoid 
ligaments. 5. Posterior face of the thy- 
roid cartilage. 6, 6. Arytenoid cartilages. 
7. Cricoid cartilage. 8, 8. Crico-arytenoid 
articulations. 9,9. Lateral crico-thyroid 
ligaments. 10. Cornu minus of the thy- 
roid cartilage. 11. Middle crico-thyroid 
ligament. 12. Ligamentous portion of 
the first ring of the trachea. 



A Front View of the Ligaments 
OF THE Larynx. — 1. Body of the os 
hyoides. 2, 2. Its appendices. 3, 3. Its 
cornua. 4, 5. Middle thyro-hyoid liga- 
ment. 6, 6. Lateral thyro-hyoid liga- 
ments. 7. Cornu majus of each half of 
the thyroid cartilage. 8. Side of the 
thyroid cartilage. 9. Its projecting 
angle. 10. Middle crico-thyroid liga- 
ment. 11. Crico-thyroid membrane. 
12. Cornu minus of each side of the 
thyroid cartilage. 13. First ring of 
the trachea. 



movements. Between the middle and lateral ligaments, 
these cartilages are connected by quite a dense structure, 
called the crico-thyroid membrane^ Fig. 79 (i i). 

The cricoid and arytenoid are connected by TWO capsular 
LIGAMENTS, Fig. 78 (s, s), wliich contain synovial membranes. 
These articulations allow of very free movement to the ary- 
tenoid cartilas^es. 

The Choed^e Yocales, or Thyro-arytenoid Ligaments, 
Fig. 81 (e, 6), consist of two on each side, one above the other. 
The inferior are sometimes called the true vocal ligaments, 
on account of their containing much more fibrous structure 
than the superior. They are composed of the yellow elastic 



OF THE LARYNX. 



199 



tissue. Tlie inferior are horizontal, while the superior are 
slightly arched upwards and outwards. They arise from 



Fio;. 80. 




A Lateral View of the 
SAME.— 1. Os hyoiUes. 2. Thy- 
ro-hyoid membrane. 3. Cornn 
majus of the thyroid cartilage. 
4. Its angle and side. 5. Cornu 
minus. 6. Lateral portion of the 
cricoid cartilage. 7. Rings of 
the trachea. 



Fig. 81. 




"A View of the Larynx prom above, 
SHOWING the Thyro-Arytenoid or Vocal 
Ligaments. — 1. Superior edge of the larynx. 
2. Its internal face. 3. Cornua majora of 
the thyroid cartilage. 4. Posterior face of 
the cricoid cartilage. 5, 5. Arytenoid car- 
tilages. 6, 6. Thyro-arytenoid ligaments. 
7. Their origin within the angle of the thy- 
roid cartilage. 8. Their terminations at the 
bases of arytenoid cartilages. 9. The glottis. 
10. Anterior part of the inferior surface of 
the cricoid cartilages. 



the angle of the thyroid cartilage, close to each other, and 
are inserted, the inferior into the anterior processes at the 
bases of the arytenoids, and the superior near their apices. 
They diverge somewhat as they proceed backwards, giving 
to the rima glottidis the shape of the letter V, Avith the angle 
pointing forwards. The inferior are covered by mucous mem- 
brane on their inner and upper surfaces, while the superior 
are covered on their inner, lower, and external surfaces. 

Tlie muscles of tlie huynx are small, and generally named 
from the parts to which they arc attached. The th3a-o-h3'oideus 
was described with the muscles of the nock. 

The Crico-Tiiyroideus, Fig. 82 (3), is quite short, and of 
a triangular shape. It arises from the anterior part of the 
cricoid cartilage, by a narrow point, and passes upwards and 
outwards to be inserted into the thyroid cartilage, occupying 



200 



DISSECTION OF THE NECK. 



tlie outer part of its lower border and inferior . cornu. The 
two thyro-hjoidei muscles leave a triangular space between 
tbem, in wbicli the middle crico-thyroid ligament is situated. 



Fig. 82. 




A Front View of the Crico-Thy- 
ROiD Muscles. — 1. Thyroid cartilage. 
2. Crico-tbyroid ligament. 3, 3. Crico- 
thyroid muscles. 4. Origin of left. 5. 
Insertion of right. 6. First ring of the 
trachea. 



Fig. 83. 




A Posterior View of the Aryte- 
noid AND Crico-Arytenoid Muscles. 
—1, 2, 3. Thyroid cartilage. 4, 4. Sum- 
mits of the arytenoid cartilages. 5, 5. 
Insertions of arytenoid muscles. C, 6. 
Cricoid cartilage. 7. Its middle portion. 
8, 9, 8, 9. Posterior crico-arytenoid mus- 
cles. 10. Posterior portion of the tra- 
chea. 11. Arytenoid muscles. 



The Crico-Aeytenoideus Posticus, Fig. 83 (s), arises 
from the posterior surface of the cricoid cartilage, passes 
obliquely upwards and outwards to be inserted into a pro- 
cess on the posterior and outer side of the base of the aryte- 
noid cartilage. 

The Arytenoideus, Fig. 83 (n), consists of transverse and 
oblique fibres. The latter are superficial, and extend from 
the base of one cartilage to the apex of the other. The 
forrn,er pass from the posterior surface of one cartilage to that 
of the other. The last-named muscles are exposed by simply 
removing the mucous membrane and some areolar tissue 
which covers them posteriorly. 

The Thyro-Epiglottici and Aryteno-Epiglottici, are 
composed of a few pale, muscular fibres, passing, the former 
from the thyroid, and the latter from the arytenoid carti- 
lages to the epiglottis, within the. folds of mucous mem- 



OF THE L'AKYNX. 



201 



brane which extend between these cartilages. They are 
more strongly developed in the larynx of some of the lower 
animals. 

The Thyro-Akyten-oideus, Fig. 84:(ii), is situated be- 
tween the ala of the thyroid cartilage, and the vocal chords 
and ventricle of the larynx. To expose this mnscle, it is ne- 
cessary to remove the posterior part 
of one of the alas of the thyroid car- 
tilage, by dividing it vertically a 
short distance behind the median line, 
and disarticulating it from the cricoid. 
It is separated frqpi the cartilage by 
some loose areolar tissue, which must 
be carefully dissected away. 

The Crico-Arytenoideus La- 
teralis, Fig. 84 (is), may be ex- 
posed by the same dissection. It 
arises from the upper border of the 
cricoid cartilage, just on the inside of 
the surface on which rests the ala of 
the thyroid cartilage, and passes 
obliquely backwards to be inserted 
into the base of the arytenoid. 

The Mucous Membrane of the 
larynx is continuous through its 
superior orifice with that of the 
pharynx, and, through its lower 
opening, with that of the trachea. It 
follows all its elevations and depres- 
sions. The lateral boundaries of the 
glottis are formed by folds of this 
membrane, which extend from the 
arytenoid cartilages obliquely up- 
wards and forwards to the sides of 
the epiglottis, thus leaving an opening between thorn of a 
triangular shape, with the base formed by the epiglottis. 
There are quite a number of mucous glands in the larynx, 
especially about the ventricles and glottis. 

The Ventrtcues, Fig. 85 (9), of the larynx are two pouches, 
one situated on each side of the rima glottidis, and lined 




a Vertical Section of the 
Larynx to SHO^y some of its 
Muscles. — 1. Cornu majtis of 
the thyroid cartilage. 2. Its 
superior border. 3. Section of 
its body. 4. Its internal sur- 
face. 5. Arytenoid cartilage. 
6. Posterior surface of the 
thyroid cartilage. 7, S, D. 
Arytenoid muscles. 10, 11, 

12. Thyro-arytenoid muscle. 

13. Crico-arytenoideus latera- 
lis muscle. 14. Cricoid carti- 
lage. 15,16,17. Crico-aryte- 
noideus posticus. IS, 19. First 
rings of the trachea as united 
by ligament. 



202 



DISSECTION OF THE NECK. 




Fig. 85. "by mucous membrane. EacL. of 

them is placed between the vocal 
chords of its own side, especially 
the superior, on the inside, and 
the thyro-arytenoid muscle on the 
outside. The sacculus laryngis is 
a projection of the ventricle up- 
wards on the outside of the supe- 
rior cord. Several mucous glands 
are found in these pouches, and 
which are pressed upon by the 
thyro-arytenoid muscles. 

The KiMA Glottidis is the space 
between the vocal chords of the two 
sides. Its form was spoken of in 
connection with the chords. This 
orifice and the glottis are subject 
to variations in size, bat the infe- 
rior, or tracheal, opening of the 
larynx remains constantly the 
same, being surrounded by the 
cricoid cartilage. 

There is, beneath the mucous 
membrane around the glottis, an 
abundance of loose areolar tissue. 
In inflammation of these parts, se- 
rum is effused in this areolar tis- 
sue ; sometimes in sufficient quan- 
tity to cause great difficulty in 
respiration, or even death. 

The arteries of the larynx are 
derived from the superior and in- 
ferior thyroid ; and it is abundantly 
supplied from these sources with 
arterial blood. 
The veins terminate in those in the immediate vicinity. 
Its nerves are the superior and inferior laryngeal branches 
of the pneumogastric, and a branch of the hypoglossal. The 
superior laryngeal enters the larynx either just above the 
thyroid cartilage, or through a foramen in this cartilage. It 
is distributed principally to the mucous membrane, although 
it sends some filaments to the muscles. The inferior laryngeal^ 



A Vertical Section of the 
Larynx, to show its Internal 
Surface. — 1. Section of the root 
of the tongue. 2. Os hyoides. 3. 
The muciparous gland of the epi- 
glottis. 4. Top of the epiglottic 
cartilage. 5. A section of its an- 
terior face. 6. A fold of mucous 
membrane from the arytenoids to 
the epiglottis. 7. Superior yocal 
ligament. 8. Section of thyroid 
cartilage. 9. Ventricle of Galen 
or Morgagni. 10. Lower vocal 
ligament. 11. Arytenoid carti- 
lage. 12, Inside of the cricoid 
cartilage. 13. Its posterior por- 
tion. 14. Lining membrane of 
the trachea. 16. End of the cornu 
majus of the OS hyoides. 16. Cornu 
majus of the thyroid cartilage. 17. 
Mucous membrane of the pha- 
rynx. 18. (Esophagus. 19. Thy- 
roid gland. 



OF THE PHAEYNX. 203 

or recurrent branch, enters the larynx at its lower and poste- 
rior part. It supplies, mainlj, the muscles with involuntary 
motor filaments. The hypoglossal branch furnishes the laryn- 
geal muscles with voluntary motor filaments. 



Sect. IY. — Dissection of the Phaeynx. 

The pharynx should be distended with hair, or something 
which may be had conveniently, for the dissection of its 
muscles. It is reached with more facility if the cervical ver- 
tebrse be first removed, or if a transverse vertical section of 
the cranium be made just in front of the occipital foramen. 
If the student has an opportunity to dissect but a single sub- 
ject, he should not sacrifice a good view of the topography 
of the interior of the pharynx, for the sake of getting a 
more distinct idea of its muscles by a special dissection. 

The following are the five muscles which enter more or 
less into the composition of its muscular walls: — 

The Infeeiok Consteictoe, Fig. 86 (7), and Fig. 87 (9), 
arises from the upper ring of the trachea, the cricoid cartilage, 
and the posterior part of the ala of the thyroid ; the fibres 
radiate as they pass backwards to be inserted into the raph^, 
which is common to the constrictors of both sides. The 
lower fibres are nearly horizontal in their direction, and cor- 
respond to the superior circular fibres of the oesophagus. 
The superior fibres are oblique, and overlap the lower part 
of the middle constrictor. 

The Middle Consteictoe, Fig. 86 (e), arises from the 
cornua of the hy oid bone, and from the stylo-hyoid ligament ; 
its fibres radiate backwards, and are inserted into the raplie. 
The upper fibres overlap the lower portion of the superior 
constrictor, from which they are separated by the stylo- 
pharyngeus muscle, and the glosso-pharyngeal nerve. It is 
connected to the base of the skull by the pharyngeal apo- 
neurosis. 

The Supeeioe Consteictoe, Fig. 8G (5), arises from seve- 
ral points, as the internal pterygoid plate, the ptcrvgo-max- 
illary ligament, and the mylo-liyoid ridge of the inferior 
maxilla. Its fibres pass backwards to be inserted into the 
raphe, and also to be connected with the pharyngeal aponeu- 



204 



DISSECTION OF THE XECK. 



rosis. 



There is quite a space between its upper border on 
each side, and the base of the cranium, which is occupied by 
the pharyngeal aponeurosis. 

The STTLO-PHARYxaEUS, Fig. 86 (i i), as its name implies, 
extends from the styloid process to the pharynx. Its fibres 



Fig. 




A Posterior View of the Muscles of the external portion of the Pha- 
rynx, AS SHOTTN BY REMOVING THE BaCK OF THE HeAD AND ThORAX. 1. Basilar 

portion of the sphenoid bone. 2. Inferior anterior portion of the os frontis, and 
crista Galli of the ethmoid. 3, 3. Petrous portions of temporal bones. 4. Levator 
palati muscle. 5. Constrictor pharyngis superior. 6. Constrictor pharyngis me- 
dius. 7. Constrictor pharyngis inferior, 8. Upper part of posterior face of the 
lining membrane of pharynx, after removing the muscle. 9. Longitudinal muscu- 
lar fibres of the cesophagus. 10. Internal pterygoid muscle. 11. Stylo-pharyngeus. 
12. Myloid attachment of the constrictor pharyngeus superior. 13. Stylohyoideus. 
14. Temporal belly of digastricus. 15. Plalysma myoides muscle. 16. Sterno- 
cleido-mastoideus. 17. Omo-hyoideus. 18. Sterno-thyroid muscle. 19. Sterno- 
hyoid. 20. Section of sterno-thyroideus. 21. Section of the trapezius mnscle. 

enter the pharynx between the superior and middle constric- 
tors, some of them to be inserted into the posterior border of 
the thyroid cartilage, and others to be lost in the pharynx. 

The Palato-Pharyxgeus belongs partly to the soft palate, 
and partly to the pharynx. It arises from the posterior 



OF THE PHAEYNX. 



205 



border of the ala of tlie thyroid cartilage, passes upwards to 
form the posterior half-arch of the palate, and then spreads 
out to be inserted into the median line of the palate, with 
its fellow on the opposite side. 



Fig. 87. 



A SIDE VIEW OF THE MuSCLES OF THE 

Pharynx. — 1. The trachea. 2. The cri- 
coid cartilage. 3. The crico-thyroid mem- 
brane. 4. The thyroid cartilage. 5. The 
thyro-hyoidean membrane. 6. The os hyoi- 
des. 7. The stylo-hyoidcan ligament. 8. 
The oesophagus. 9. The inferior constrictor. 
10. The middle constrictor. 11. The supe- 
rior constrictor. 12. The stylo-pharyngeus 
muscle passing down between the superior 
and middle constrictor. 13. The upper con- 
cave border of the superior constrictor ; at 
this point the muscular fibres of the pha- 
rynx are deficient. 14. The pterygo-maxil- 
lary ligament. 15, The buccinator muscle. 
16. The orbicularis oris. 17. The mylo-hy- 
oideus. 




The Pharyngeal Aponeurosis is thick and strong at the 
upper part of the pharynx, where it serves to connect its 
muscular walls to the base of the cranium, and to complete 
them in this part of it. As it descends, it gradually becomes 
thinner, until it ends in areolar tissue. It is situated between 
the mucous membrane and muscular layer. 

The arteries of the pharynx are obtained principally from 
the ascending pharyngeal; it also receives small branches 
from, the superior thyroid, the palatine and the phaiyngeal 
branches of the internal maxillary. 

The nerves come from the pharyngeal plexus, which con- 
sists of sensor and involuntary motor filaments derived from 
the glosso-pharyngeal, pneumogastric, and sympathetic. 

The pharynx is separated from the vertcbni3 by the longus 
colli and rectus capitis anticus major muscles. 

The anatomy of the trachea and oesophagus will be 
described, the former in connection with the bronchi and 
lungs, and the latter with the contents of the mediastinum. 
18 



PART II. 

DISSECTION OF THORAX, BACK, AND UPPER EXTREMITY. 



CHAPTER I. 

THE UPPEE EXTEEMITY. 

Sect. I.— Dissection of the Pectoral and Axillary 
Regions. 

Before commencing the dissection of these parts, the stu- 
dent should make himself familiar with the prominent points 
around the shoulder and axilla. He should also notice the 
outlines of the thorax, the regions into which it is divided 
for the purposes of auscultation and percussion, the position 
of the mammae, and the degree in which these various regions 
are subcutaneous or covered bj muscles. 

It will be perceived that the sternum is partly subcuta- 
neous, also the clavicle, with the acromion process, and spine 
of the scapula. The position of the coracoid process of the 
scapula should be ascertained, and its relations to the clavicle 
and acromion process carefully observed. The position of 
the upper extremity should be varied so as to show tlie move- 
ments of the clavicle and scapula, and any changes which 
may occur in the general configuration of the parts. 

An incision may now be made through the skin and super- 
ficial fascia, commencing at the middle of the upper border 
of the sternum, and extending along the clavicle to the acro- 
mion process. Another may then be made along the median 
line of the sternum, to the xiphoid cartilage; and a third from 
the sterno-clavicular articulation, to the insertion of the pec- 
toralis major. The skin may now be raised by reflecting one 
flap towards the shoulder, and the other towards the lower 
border of the pcctoralis major. In case the abdomen is being 



208 



THE UPPER EXTREMITY. 



dissected at tlie same time, it may be convenient to carry tlie 
last incision from the xiphoid cartilage along the lo^rer 
border of the pectoral muscle, since the parts belonging to 
both the upper and lover extremities are here more or less 
blended. In this way the same incision, as far as the origin 
of the pectoralis major is concerned, -^dll answer for both. 
The portion of skin covering the serratus magnus may 
be left till the student is ready to dissect the axilla, when it 
may be reflected off in a single flap. 

The integument of the pectoral region demands no particu- 
lar notice. 

Its nerves are derived partly from the supra-cla^acular, Tig. 
103 (i). and supra-acromial. Tig. 101: (i), branches of the 
cervical plexus, which descend from the neck over the cla- 
vicle and sternum, and partly from the anterior cutaneous 
branches of the intercostals, which perforate the intercostal 
spaces along the border of the sternum, and ramify in the 
subcutaneous fascia ; a branch of the second intercostal nerve 
anastomoses with a branch of the supra-clavicular. 

The cutaneous arteries come from the internal mammary, 
and from the thoracic branches of the axillary. The largest 
of them are distributed to the mammary gland. 

There is only one vein of any importance superficial to 
the deltoid and pectoralis major muscles, 
Fig. 88, and this is the cejAcdic^ which occupies 

the groove corresponding to the juxta- 
position of these muscles. In removing 
the skin and fascia, the student should 
look for this vein and the humeral 
branch of the thoracico-acromial artery 
which accompanies it. 




The Mam:mary Gla2s-d, Fig. 88, should 
be examined in situ: its lobulated ar-. 
rangement ; its appearance as contrasted 
with the surrounding tissues; the man- 
ner in which it is connected with the 
fascia, and its relations to the pectoralis 
major and the thorax generally. 

Its arteries and nerves are derived 
from the same sources as those of the 
skin in its vicinity. Its lymjjliatics are connected T^dth those 



A Side View of the 
Mammary Glaxd. 



DISSECTION OF THE AXILLAEY REGION. 



209 



Fig. 



of the axilla, and also with others in the cavity of the 
thorax. 

The size of the gland varies greatly. In the female it is 
much larger than in the male. The nipple is situated a little 
to the inner side of the centre. It is surrounded by an are- 
ola, the tint of which, in the female, depends on several cir- 
cumstances, as complexion, menstruation, 
pregnancy, &c. The surface of the mam- 
ma appears smooth, the spaces between 
the lobules being filled with fat. There 
is not, however, usually much fat beneath 
the skin around the nipple. 

The lactiferous tuhes^ Fig. 89, in the nipple, 
vary from fifteen to twenty-three or four. 
These tubes are wholly independent of 
each other ; so, also, are the various smaller 
ducts of the different lobules, which pro- 
ceed from the radicles, and unite to form 
them ; hence, if one of these tubes shall 
become closed during lactation, the milk 
will necessarily be accumulated in all the 
smaller tubes of which that is a common 
outlet. 

There are small glands on and around 
the nipple, for the purpose of supplying a 
lubricating secretion. 

The importance of supporting the mam- 
mae during lactation, and especially if suf- 
fering from inflammation, will be suggested 
by their position and means of attachment 
to the thorax. 

There is generally very little fat in the 
subcutaneous fascia or areolar tissue in this 




A Vertical Sec- 
tion OF THE MaMMARTT 

Gland, showing its 
Thickness and the 
Origins of the Lac- 
tiferous Ducts. — 1, 
2, 3. Its pectoral sur- 
face. 4. Section of the 
skin on the surface of 
the gland. 5. The thin 
skin covering the nip- 
ple. 6. The lobules 
and lobes composing 
the gland. 7. The lac- 
tiferous tubes coming 
from the lobules. S. 
The same tubes col- 
lected in the nipple. 



The deep or special fascice consist of one investing the pecto- 
ralis major, and another covering the deltoid. Tlie pectoral 
fascia is continuous from the lower border of the great pecto- 
ral muscle, across the axilla to the latissimus dorsi ; also with 
the fascia of the arm. Externally, it dips down between the 
deltoid and pectoralis major muscles, along with the deltoid 
fascia, which is inserted below into the deltoid ridge, and is 

18* 



210 THE UPPER EXTREMITY. 

continuous behind with tlie infra-spinata fascia and tliat of 
the arm or the brachial fascia. These fasci{» should be studied 
with reference more particularly to the formation of abscesses 
beneath them. 

The deep fascia may now be raised by making an incision 
throuo-h it from the sterno-clavicular articulation to the in- 
sertion of the pectoralis major. The student, in this way, 
will be able to raise the fascia so as to trace its continuity as 
described above, at the same time that he exposes the pecto- 
ralis major. The deltoid fascia may be raised in the same 
manner from the deltoid muscle, although it will be sufficient 
to expose only the anterior half of this muscle at the present 
time. 

The Pectoralis Major, Fig. 90 (7, 1 0), arises from the 
inner half of the clavicle, the anterior surface of the sternum, 
the cartilages of the second, third, fourth, fifth, and sixth 
ribs, and by a slip from the aponeurosis of the external ob- 
lique. From this broad origin the fibres converge, and are 
inserted^ by a flat tendon, into the anterior margin of the 
bicipital groove on the humerus, and into the brachial fascia. 
From the extensive origin and narrow insertion of this mus- 
cle, the student will see the necessity of the difference which 
exists in the direction of its fibres, and the effects of different 
portions of the muscle acting separately. The lower fibres 
are nearly horizontal, while the upper are vertical in their 
direction. The upper part of the muscle is inserted lower 
down than the inferior portion, which causes a sort of 
doubling of the tendon. The action of this muscle varies; 
if the clavicular portion alone acts, it will draw the arm up- 
wards and forwards, the sternal will move it directly forwards, 
while the lower part will draw it downwards and forwards ; 
the entire muscle will bring the arm inwards and forwards. 
If the humerus be elevated and fixed, then the lower part of 
the muscle will raise the ribs and draw them outwards so as 
to assist in expanding the thorax. If the hand be supined, 
it is capable of pronating it by rotating the humerus inwards. 
The clavicular portion is usually separated from the costo- 
sternal by areolar tissue. This fissure is sometimes quite 
large, and extends some distance towards the insertion of the 
muscle ; again, it is scarcely perceptible. An areolar inter- 
space also separates this muscle from the deltoid. In this 



DISSECTION OF THE AXILLARY REGION. 



211 



space are found tTie cephalic vein and the humeral branch, Fi| 
94, of the tlioracico-acromial artery. 

Fig. 90. 




A View of the Superficial Muscles of the Upper Front op the Trunk. — 
1. Sterno-hyoid. 2. Sterno-cleido-mastoid. 3. Sterno-thyroid. 4. Clavicular 
portion of the sterno-cleido-mastoid. 5. Anterior edge of the trapezius. 6. Clavicle. 
7. Clavicular origin of the pectoralis major. 8. Deltoid. 9. Fold of fibres of the 
pectoralis major on the anterior edge of the axilla. 10. Middle of the pectoralis 
major. 11. The crossing and interlocking of the fibres of the external oblique of 
one side of the abdomen with those of the other. 12. Biceps flexor cubiti. 13. 
Teres major. 14. Serratus magnus anticus. 15. Superior heads of the external 
oblique interlocking with the serratus magnus. 



The pectoralis major may now be raised from its origin, 
taking care to observe the nerves and arteries which pene- 
trate its under surface. 

The nerves come from the axiRary, and consist of one or 
two branches, called the siipcrior thoracic, Fig. 93. The arteries 
are branches of the superior thoracic and thoracica acro))uah's, 
Fig. 92, which arise^most frequently, by a common trunk, 
from the axillary arterj^ The pectoralis major should be 



212 THE UPPEE EXTKEMITY. 

raised with a view of replacing it so as to stuclj its relations 
to the axilla. 

Instead of detaching the entire muscle from its origin, the 
student may turn down the clavicular portion at first, and 
dissect down to the axillary vessels and nerves, which will 
afford him a good view of the surgical relations of the upper 
part of the axillary artery. In this way, he will be able to 
obtain a correct idea of its depth, and what parts are neces- 
sarily involved in cutting down upon it just below the cla- 
vicle. In doing this, the following parts will be seen : — 

Having turned the clavicular portion of the pectoralis 
major down to the extent of about three inches, the costo- 
clavicular aponeurosis will be brought into view. This is at- 
tached to the first rib, the clavicle, and the coracoid process, 
and is reflected downwards over the pectoralis minor. 

Coming through this fascia, and close to the upper border 
of the pectoralis minor, will be observed the superior thoracic 
and thoracico-acromial arteries^ Fig. 92 (11,12); the first going 
to the pectoralis major, and the last towards the deltoid 
muscle, to divide into its acromial, humeral, and thoracic 
branches. The acromial branch is distributed to the parts in 
the neighborhood of the acromion process ; the humeral enters 
the fissure between the deltoid and pectoralis major, to be 
distributed principally to the former muscle ; the thoracic 
branch goes to the latter muscle. These arteries send branches 
to the skin and fascia crossing the muscles. 

The SuPEEiOR Thoracic Nerve, which arises behind the 
clavicle, perforates this fascia, and accompanies the artery of 
the same name to the pectoralis major. 

The Cephalic Yeik, after passing up in the groove be- 
tween the deltoid and pectoralis major to near the clavicle, 
dips beneath the latter muscle, and passes transversely across 
to terminate in the axillary vein, which lies close to the tho- 
rax. Fig. 94. There are other veins in this region which 
open either into the cephalic, or directly into the axillary, 
but they are small, and have no practical importance. 

Eemoving the fascia and areolar tissue, the upper border 
of the pectoralis miiior below, and the subclavius muscle^ Fig. 
91 (3, 12), above, will be seen separated by a space somewhat 
triangular in shape. In this space, and occupying a plane 
deeper than these muscles, are the axillary vein, artery, and 



DISSECTION OF THE AXILLAKY EEGION. 213 

nerves^ Figs. 93, 94. The artery is situated between the vein 
on its thoracic side, and the nerves on its humeral side. 
The artery is deeper seated than the vein, and the nerves are 
situated on a plane deeper than it. 

In making this dissection, there is nothing destroyed which 
the student will have any occasion to examine afterwards ; 
nor is it so complex as to prevent any one from making it, if 
he will exercise a little patience ; and, when finished, he will 
have the satisfaction of seeing at once how the knowledge 
which he has acquired can be applied in practice ; for he can 
now tell, from his own observation, which parts would have 
to be divided, what parts should be avoided, and how deep 
an incision would be required to reach the axillary artery in 
the upper part of its course. He has now a picture fixed in 
his mind, made up of several details, which sustain a certain 
relation to each other, and all of them to the main object in 
the whole group or picture. He will ]iot be likely to forget 
the special anatomy of parts when their surgical relations are 
thus fixed in his mind. He sees, for instance, the clavicular 
portion of the pectoralis major, the manner in which it covers 
the pectoralis minor and the subclavius, with the space 
between them ; how this space is filled iip with a fascia which 
is perforated by small vessels and nerves; how the great 
arterial trunk, which is destined to supply nearly the whole 
of the upper extremity with arterial blood, enters the axilla; 
how the great venous trunk, which is required to return this 
blood, leaves the axilla; and how the nerves enter the same 
space preparatory to dividing and subdividing to go to every 
part of the upper extremity. 

The pectoralis major having been separated from its con- 
nections, except its insertion, the p)<^cloralis minor now comes 
into view. 

The Pectokalis Minor, Fig. 91 (12), arises from the se- 
cond, third, fourth, and fifth ribs, sometimes from but three, 
and is inserted iQwdmon^^ into the coracoid process, near its free 
extremity. Its tendon is connected with the coraco-brachialis 
and short head of the biceps, and frequently by a fibrous 
band with the triangular, or capsular, ligament of the shoulder 
joint. It forms a part of the anterior wall of the axilla, 
leaving a space above and below to be formed by the pocto- 



214 



THE UPPER EXTREMTTT. 



ralis major, the fibres of wliicTi it crosses nearly at a riglit 
angle. By observing its attachments, and the direction of 
its fibres, it will be seen that it can draw the scapula down- 
wards, forwards, and inwards ; or when the shoulder is carried 
upwards and backwards, and fixed in this position, it can 
elevate the ribs from which it takes its origin. Thus bj 
placing the arm and shoulder in a proper position, both the 
pectoral muscles become powerful agents in expanding the 
upper part of the thorax. 

In raising this muscle, the dissector should look for the 
inferior thoracic artery and nerve^ Figs. 92, 93, which penetrate 
its under surface. The nerve is quite small, and comes from 
the plexus behind the muscles, and passes between the axil- 
lary artery and vein. This artery varies very much in its 
origin, as do all the branches of the axillary artery. 

Fig. 91. 



A VlE"W OF THE DeEFER- 

SEATEi) Muscles ox the 
Upper Front of the 
Trunk. — 1. Cut portion of 
thesterno-cleido-mastoid. 2. 
Scalenus medius. 3. Scale- 
nus anticus. 4. Trapezius. 5. 
Omo-hjoid. 6. Sterno-tby- 
roid. 7. Sterno-hyoid. 8. 
Subclavius muscle. 9. First 
external intercostal. 10. In- 
sertion of the pectoralis mi- 
nor. 11. Cut portion of the 
coraco-brachialis and short 
head of the biceps. 12. Body 
of the pectoralis minor. 
13. An external intercostal 
muscle. 14. Subscapularis. 
15. Latissimus dorsi. 16. 
Serratus magnus. 




The Subclavius Muscle, Fig. 91 (s), arises tendinous from 
the cartilage of the first rib, and is inserted into the under 



DISSECTION OF THE AXILLARY EEGION. 215 

surface of the outer part of the clavicle. It can draw the 
acromial extremity of the clavicle downwards and forwards, 
thus assisting other muscles in moving the shoulder in this 
direction ; or when the shoulder is fixed in an opposite direc- 
tion, it can assist in elevating the ribs. This muscle is placed 
between two layers of the costo-clavicular aponeurosis. Its 
relations to the axillary vessels and nerves should be ob- 
served. 

The Axilla is now fairly exposed, the whole of its ante- 
rior wall being removed. The beginner will be able to 
dissect and study, at least^ the principal vessels and nerves, 
preparatory to a more thorough investigation of its contents, 
in his future dissections of this region. 

Some of the Ij^mphatic glands may be looked for before 
proceeding to dissect the vessels and nerves. There are 
several of these glands situated just behind the lower border 
of the pectoralis major, which are connected with the lym- 
phatics of the mammary gland. Another chain is found at 
the border of the latissimus dorsi ; and others are scattered 
through the axilla. Not unfrequently these glands are met 
with in the dissecting-room enlarged from disease. 

In dissecting the vessels and nerves of the axilla, much 
may be done with the handle of the scalpel. They are im- 
bedded in loose areolar tissue, which can be separated from 
them without much cutting. A good deal of this can be 
done by introducing the scissors at different points with the 
blades shut, and then opening them; in this way there is no 
danger of cutting anything, and when properly done, no 
occasion for breaking any of the vessels or nerves. 

The Axillary Artery, Fig. 92 (9), extends from the 
first rib to the lower border of the tendon of the pectoralis 
major. It is a continuation of the subclavian. Its direction 
varies with the position of the arm. When the arm is de- 
pendent, it forms nearly a right angle with the subclavian ; 
but when the arm is elevated to a right angle with the body, 
it forms nearly a straight lino with that artcr}^ The recol- 
lection of this fact may be of some importance in keeping 
the arm in a proper position, in reducing luxations of the 
humerus, especially if sufficient time has elapsed for adhe- 
sions to be formed. 



216 



THE UPPEE EXTEEMITY. 



This artery may be divided into three portions : one above 
the pectoralis minor, one below it, and another directly be- 
hind it. The relations of the upi^er division have already 
been described. In the middle part of its course it is sur- 

Fig. 92. 




1. The deltoid muscle, 2. The biceps. 
3. The tendinous process given off from the 
tendon of the biceps to the deep fascia of 
the forearm. It is this process which sepa- 
rates the median basilic vein from the bra- 
chial artery. 4. The outer border of the 
brachialis anticus muscle. 5. The supinator 
longus. 6. The coraco-brachialis. 7. The 
middle portion of the triceps muscle. 8. 
Its inner head. 9. The axillary artery. 10. 
The brachial artery; a dark line marks the 
division between these two vessels. 11. The 
thoracica acromialis artery dividing into 
its three branches; the number rests upon 
the coracoid process. 12. The superior and 
inferior thoracic arteries. 13. The serratus 
magnus muscle. 14. The subscapular artery. 
The posterior circumflex and thoracica axil- 
laris branches are seen in the figure between 
the inferior thoracic and subscapular. The 
anterior circumflex is observed, between the 
two heads of the biceps, crossing the neck 
of the humerus. 15. The superior profunda 
artery. 16. The inferior profunda. 17. The 
anastomotica magna inosculating inferiorly 
with the anterior ulnar recurrent. 18. The 
termination of the superior profunda, inos- 
culating with the radial recurrent in the in- 
terspace between the brachialis anticus and 
supinator longus. 



ronnded by the axillary plexus. Fig. 93, and is never ligated 
at this point unless in cases of amputation. 

The loicer division is the most superficial. It can be 
reached here very readily from the axillary fossa. At first it 
usually lies between two roots of the median nerve, and then 
behind and a little to the thoracic side of this nerve. The 
external cutaneous nerve is situated on its outer side, between 
it and the coraco-brachialis muscle, which it very soon per- 
forates. The internal cutaneous is seen on its inner side. This 
nerve is quite small, and should not be confounded with the 



DISSECTION OF THE AXILLARY EEGION". 



217 



lesser internal cutaneous, which, lies close to it on the inner 
side. The ulnar is just behind the internal cutaneous, and 
to the inside of the artery ; this is about the size of one of 
the roots of the median nerve. Behind the ulnar nerve, and 
partly behind the artery, is the musculo-spiral nerve. This is 
quite as large as the median nerve. The circumflex nerve is 
directly behind the artery. If the student will make the 



Fig. 93. 



A View of the Brachial 
Plexus of Nerves and Bran- 
ches TO THE Arm. — 1, 1. The 
scalenus anticus muscle, behind 
which are the roots of the plexus. 
2,2. The median nerve. 3. The 
ulnar nerve. 4. The branch to 
the biceps muscle. 6. The nerve 
of Wrisberg. 6. The phrenic 
nerve from the 3d and 4th cer- 
vical. 




artery his guide, he will have no difficulty in finding and 
distinguishing these six nerves, or divisions of the axiHarv 
plexus. They are described here because the dissection of 
the artery necessarily involves them, while the dissection of 
the nerves exposes the artery. 

The axillary artery is usually represented as giving olY 
19 



218 THE UPPER EXTREMITY. 

in all seven brandies. These are named tlie superior and 
inferior thoracic, the thoracica acromialis, the thoracica axil- 
laris, the sabscapular, and the anterior and posterior cir- 
cnmflex. The first named four are very irregular in their 
origin. The superior thoracic and the thoracica acromialis 
usually have a common origin just behind the upper border 
of the pectoralis minor. The distribution of these has 
already been described. The inferior thoracic and the tho- 
racica axillaris require no special notice. The three remain- 
ing branches are more regular in their origin. 

The Subscapular, Fig. 92 (i 4), usually arises opposite the 
lower border of the subscapularis muscle ; it may come off 
higher up, or it may arise in common with some other artery. 
It runs a short distance on the lower part of the subscapu- 
laris, when it gives off a large branch to go to the dorsum of 
the scapula ; this is the arteria dorsalis scapuloe. It then con- 
tinues downwards and backwards on the posterior wall of 
the axilla to be distributed to the sn.bscapularis, teres major, 
latissimus dorsi, and serratus magnus. 

The Anterior Circumflex may consist of one or two 
small branches, and frequently comes from the posterior cir- 
cumflex. It passes transversely outwards beneath the coraco- 
brachialis, biceps, and deltoid muscles, and over the anterior 
part of the surgical neck of the humerus. It is distributed 
to the muscles above mentioned, and to the shoulder-joint. 

The Posterior Circumflex is much larger. It passes 
behind the surgical neck of the humerus, and thus reaches 
the under surface of the deltoid, to which it is principally 
distributed. The student will not be able to trace these 
arteries, for the present, beyond the axilla. 

The Axillary Yein, Fig. 94 (2), lies to the thoracic side 
of the artery in the upper part of the axilla, but gets some- 
what in front of it in the lower part. The cephalic vein ter- 
minates in it just below the clavicle; the basilic opens into 
it in the lower part of the axilla; sometimes the axillary 
vein seems to be a continuation of the basilic. The basilic 
may join the vense comites before it reaches the axilla. 
There are other veins which empty into the axillary ; they 
correspond to the arteries which have been described, and 
require no particular notice. 



DISSECTION OF THE AXILLARY REGION. 



219 



Besides the tlioracic nerves and the divisions of the axil- 
lary plexus, there are two or three 
subscapular branches, the long tho- 
racic or external respiratory nerve 
of Bell, and the nerve of Wrisberg, 
to be noticed in this dissection, 
Fig. 93. 

The Subscapular arise from the 
outer part of the plexus, and rest 
on the subscapularis muscle, which, 
together with the teres major and 
latissimus dorsi, they supply. 

The Long Thoracic arises from 
the fifth and sixth cervical, and at 
first lies behind the axillary plexus, 
then gets between it and the serratus 
magnus, on which it rests as it de- 
scends, vertically, nearly to its lower 
border. It sends filaments to this 
muscle throughout its course. Ke- 
coUecting its relations to the serratus 
magnus, the dissector cannot well be 
at a loss in finding it. 

The Lesser Internal Cutaneous 
is a branch of the axillary plexus. 
It is sometimes called the nerve of 
Wrisberg. At first it is behind the 
axillary vein, but soon gets to the 
inner side of it, when it gives off 
one or more branches to anastomose 
with the intercosto-humeral. It then 
passes down the arm on the inner side 
of the basilic vein, pierces the fascia 

The Supkrficial Vkins on the Front op the ITppEn Extuemitt. — 1. Axil- 
lary artery. 2. Axillary vein. 3, Basilic vein, where it enters the axillary. 4.4. 
Portion of tlic basilic vein which passes under the brachial fascia; a portion of tho 
vein is frcoil from the fascia. 5. Point where tho median basilic joins the basilic 
vein. C. Points to tho posterior basilic vein. 8, Anterior basilic vein. 9. Point 
whore the cephalic outers the axillary vein. 10. A portion of the same vein as 
seen under the fascia; the rest is freed from it. 11. Point where the median ce- 
phalic enters the cophnlic vein. 12. Lower portion of the cephalic vein. l;>. Me- 
dian cephiilie vein. It. Median vein. 15. Vena communicans. 1(). Cephalica- 
pollicis vein. 17. (Subcutaneous veins of tho lingers. 18. fc?ubeutaneous palmar 
veins. 




220 



THE UPPER EXTREMITY. 



some distance above tlie elbow, and is distributed to the skin 
on the inner side of the arm. 

The IXTERCOSTO-HuMERAL is a branch of the second inter- 
costal nerve ; it enters the axilla by perforating the intercostal 
muscles in the second intercostal space, about midway between 
the sternum and the vertebral column. It traverses the lower 
and posterior part of the axilla, and is distributed to the in- 
tegument of the upper, inner, and posterior part of the arm. 
It is connected, as before mentioned, to the lesser internal 
cutaneous nerve, by one or more filaments. Several other 
small cutaneous hranches may also be observed when a careful 
dissection of the axilla is made. 

Besides the intercosto-humeral nerve, just described, several 
of the jDosterior cutaneous hranches of the intercostal nerves will 
be met with in this dissection. They are, however, quite 
small. They perforate the intercostal muscles below the 
second intercostal space, and are lost in the integument. 

The Serratus Magnus, Fig. 95 (5, e, 7), is a very broad 

Fig. 95. 




A Lateral Vietv of the Deep- 
seated Muscles of the Trujtk:. 
— 1. Vertebra. 2. First rib. 3. 
Superior origin of the serratus 
magnus. 4. Acromion scapulae. 
5, 6^ 7. Show the convergence of 
the fibres of the serratus magnus 
and its insertion into the -whole 
base of the scapula. 8. An ex- 
ternal intercostal muscle. 9. Sec- 
tion of the sacro-lumbalis. 10. 
Transversalis abdominis. 11. Ab- 
dominal aponeurosis. 12. Rectus 
abdominis. 13. Fascia lumborum. 
14, 14. Costal origins of the ser- 
ratus magnus. 15. External in- 
tercostal muscle. 16, 16. Two 
internal intercostal muscles. 



DISSECTION OF THE AXILLARY REGION. 221 

muscle, forming tlie inner or thoracic wall of the axilla. It 
arises from the superior nine ribs bj as many fleshy digita- 
tions, the inferior four or five of which project in between the 
heads of the external oblique, and is inserted into the whole 
length of the base of the scapula. The lower fibres pass up- 
wards and backwards, while the upper fibres have nearly a 
horizontal direction. This muscle is capable of acting either 
on the ribs or the scapula. "When the ribs are fixed, it draws 
the scapula forwards. If the lower or upper part act separ- 
ately, it will rotate the scapula on its axis. If the shoulder 
be carried backwards and fixed in this position, this muscle, 
especially the lower part of it, will elevate the ribs, thus co- 
operating with other muscles in expanding the thorax. That 
portion of it which arises from the second, third, and fourth 
ribs, is quite thin. Between it and the ribs and intercostal 
muscles is an abundance of loose areolar tissue, which allows 
of a free gliding movement. This muscle should not be 
divided until the dissector is ready to detach the arm from 
the trunk. It is not very easy to make a clean dissection of 
the serratus magnus unless the clavicle is disarticulated from 
the sternum, and detached from the first rib, so that the scap- 
ula can be drawn backwards and separated widely from the 
thorax. 

The SuBSCAPULARis arises, Fig. 96 (19), from the whole 
of the thoracic surface of the scapula ; the fibres converge as 
they pass upwards and forwards to form a short tendon, which 
is inserted into the lesser tuberosity of the humerus. It passes 
beneath the coracoid process, and over the neck of the hu- 
merus, its tendon being blended more or less intimately with 
the capsular ligament of the shoulder-joint. Between the 
tendon and neck of the humerus is a large bursa, which 
frequently communicates with the joint. Sometimes there 
are two or three intermuscular septa, which seem to divide 
the muscle into three or four parts. It assists in keeping the 
liead of the humerus applied to the glenoid cavity ; or, it can 
draw the arm to the thorax, or rotate the humerus inwards. 
The action of the nmscles around the shoulder-joint should 
be studied, when they have all been dissected, as constitut- 
ing a group. 

The Teres Major arises, Fig. 96 (t 4), from a flat surf^ioe 
near the inferior angle of the scapula; it passes forwards, and 

19-^- 



222 



THE UPPEE EXTEEMITY. 




somewliat upwards, and is inserted^ by a broad tbin tendon, 
into tbe posterior part of tbe bicipital groove of tbe bnmerus. 

Fig. 96. 

An Anterior View of the 
Muscles of the Shoulder. — 
1. Upper part of the body of the 
scapula. 2. Supra-spinatus mus- 
cle. 3. Section of acromion pro- 
cess. 4. Coracoid process. 5. 
Origin of the second or short 
head of the biceps. 6. Subsca- 
pularis near its insertion. 7. 
Deltoid. 8. Tendon of the pec- 
toralis major. 9. Insertion of 
the deltoid muscle. 10. Brachi- 
alis anticus. 11. Cut extremity 
of the 03 humeri. 12. Triceps 
extensor cubiti. 13. Tendon of 
the latissimus dorsi. 14. Teres 
major. 15. Axillary portion of 
the latissimus dorsi. 16. Lower portion of the subseapularis. 17. Origin of 
the teres major. 18. Lower portion of the scapula. 19. Middle portion of the 
subseapularis. 

Its tendon is closely connected witb tbat of tbe latissimus 
dorsi ; altbougb a small bursa is commonly found between 
tbem and near tbeir insertion. A triangular space will be 
noticed between tbis muscle and tbe lower border of tbe 
subseapularis, witb its base corresponding to tbe surgical 
neck of tbe bumerus. 

Tbe circumflex nerve and tbe posterior circumflex artery will 
be seen going backwards tbrougb tbis space close to tbe 
bumerus, wbile tbe dorsal hranch of tbe subscapular artery 
passes tbrougb it nearer to tbe apex. 

Tbe Long Head of tbe Tkiceps Extensoe Cubiti, Fig. 
96 (12), may be seen at tbis stage of tbe dissection, crossing 
tbis space vertically bebind tbe teres major. 

Tbe Latissimus Doesi, Fig. 96 (i 3), is necessarily exposed 
in its upper part in tbe dissection of tbe axilla, of wbicb it 
forms, witb tbe teres major, tbe lower part of the posterior 
wall of tbat space. It lies, at first, in tbis region, on tbe out- 
side of tbe teres major, tben below it, and finally anterior to 
it. It is inserted into tbe postetior part of tbe bicipital groove 
by a tbin, broad tendon, wbicb usually extends a little higher 
up than that of the teres major. 

The student should now review what he has dissected. 



DISSECTION OF THE BACK. 223 

sliould replace tlie muscles wliicli have been partially de- 
tached, and get a distinct idea of the boundaries of the axilla, 
and the relations of the vessels and nerves to these boundaries. 
This is a most important region, and cannot be too carefully 
studied with reference to abscesses or tumors occurring in 
the axilla, fractures of the clavicle, luxations of the head of 
the humerus, ligation of the axillary artery, &c. The coraco- 
brachialis and the two heads of the biceps flexor have been 
exposed, to some extent, but the dissection of these muscles 
had better be postponed till the arm has been detached from 
the trunk. 



Sect. II. — Dissection of the Back. 

The subject should now be turned over, so that the back 
can be dissected preparatory to removing the upper ex- 
tremity. It will not interfere materially with the dissection 
of the head and neck, and lower extremities, whenever it is 
done, as those who are dissecting these parts can attend to 
the dissection of the back almost as well at one time as ano- 
ther. When several are dissecting on the same subject, some 
arrangement should be entered into in the dissection of the 
back, by which some of the class may be at work while the 
rest are engaged in reading a description of the parts to be 
examined. In this way, each member of the class may have 
the full benefit of the dissection. 

The subject should be placed on the forepart, with the tho- 
rax elevated, by placing blocks beneath it. The muscles are 
to be made tense by placing the subject in such a position 
as will effect this object, which can be readily ascertained 
by the student himself. It may be necessary to place a small 
block under the pelvis, or to allow the head to hang over 
the end of the table. The arras and shoulder are to be so 
placed as to put the muscles attached to the clavicle, sca- 
pula, and humerus on the stretch. It is impossible to make 
a good dissection of the back unless the position of the difter- 
ent ])arts concerned is properly, attended to. 

The first incision is to be made through the skin and in 
the median line from the occiput to the lower part of the 
sacrum. If it be intended to examine the subcutaneous 
fascia, it is a matter of little consequence in what direction 



224 THE UPPER EXTREMITY. 

tlie other incisions tlirougb. the skin are made. To expose 
the muscles by cutting do'wn on them at once, or by dis- 
secting off the fascia after the skin has been removed, the 
incisions should be made in the direction of the fibres of the 
muscles. There is nothing in particular connected with the 
subcutaneous fascia on the back which requires notice, ex- 
cept the cutaneous nerves and vessels ; and even these are 
not of sufficient practical importance to warrant the student, 
as a general thing, devoting much time to their dissection. 

The Kerves are derived from the posterior divisions of 
the spinal nerves. The first cervical gives off, ordinarily, 
no cutaneous branch. The second sends a large branch to 
the scalp, which accompanies the occipital artery. The third 
cervical usually sends also a small cutaneous branch to the 
back of the head. The rest of the cervical nerves ramify in 
the integument of the back of the neck. The cervical and 
dorsal perforate the trapezius, while the six lower dorsal 
perforate the latissimus dorsi and trapezius to reach the 
skin. Those below the dorsal perforate the latissimus dorsi. 
They perforate these muscles near the spinous processes, and 
for the most part are directed outwards. These nerves are 
easily traced from the intervertebral foramina, especially 
when a dissection is made for this purpose. They will be 
met with from time to time in the dissection of the muscles. 

The Arteries are derived from the occipital, the trans- 
verse humeral, the posterior cervical, the intercostal, and the 
lumbar. It is not necessary to give any description of these 
arteries in connection with the fascia of the back. 

Extending from the occipital protuberance to the spinous 
processes of all the cervical vertebra3, except the atlas, will 
be found yellow elastic tissue, named the ligamentum nuduB. 
This is large in some of the lower animals, but in man it is 
often quite small and indistinct. Some of the muscles of 
the neck are attached to this ligament. It assists in support- 
ing the head. 

To dissect the Trapezius, Fig. 97 (i, 2), an incision may 
be made through the fascia, or through the skin and fascia at 
the same time, from the first dorsal vertebra, or near it, trans- 
versely across to the spine of the scapula. One flap may be 
dissected upwards and the other downwards until the whole 



DISSECTION OF THE BACK. 225 

muscle is exposed. In making this dissection, tlie student 
requires no other guide than that afforded by the fibres of 
the muscle. The direction of these he will see distinctly re- 
presented in the drawing of the muscles of the back. In 
the upper part of the neck, this muscle is frequently very 
small. It arises from the superior ridge an the occipital 
bone, from the ligamentum nuchae and the spinous processes 
of the lower cervical and all the dorsal vertebrae ; from this 
extensive origin the fibres converge and are inserted into the 
posterior third of the clavicle, the acromion process, and the 
spine of the scapula. The fibres of the lower part pass ob- 
liquely upwards, while those of the upper part pass obliquely 
downwards; the middle fibres have a transverse direction. 
When the entire muscle acts, it draws the shoulder back- 
wards. When the upper part acts separately, it may draw 
the shoulder upwards and backwards ; when the lower part 
acts separately, it may draw the shoulder downwards and 
backwards. If the shoulder be fixed, this muscle may draw 
the head backwards and to one side ; both the trapezii acting 
at the same time would draw the head directly backwards. 
That portion of the muscle which arises from the lower 
cervical and upper dorsal vertebrae is aponeurotic for some 
distance from its origin. The student should be careful not 
to remove this tendon with the fascia. The lower part of 
the muscle, where it passes over the spine of the scapula, is 
also aponeurotic. 

To expose the Latissimus Doesi, Fig. 97 (4), the trape- 
zius must be detached from the lower dorsal vertebra3 and 
turned upwards. The arm should also be drawn upwards 
to make its fibres tense. It arises from the spinous processes 
of the six lower dorsal and all the lumbar vertebras, from the 
dorsum of the sacrum, the posterior third of the crest of the 
ilium, and also from the inferior three or four ribs. The 
fibres pass upwards and forwards, and are inserted by a thin 
tendon into the bicipital groove of the humerus. The 
lumbar portion of it is, principally, aponeurotic, and forms 
the posterior layer of the lumbar fascia. The fleshy slips 
by which it arises from the ribs indigitatc with the heads of 
the posterior part of tlie external oblique. 

The upper part of this muscle is much thinner than the 
lower ; it glides over the inferior angle of the scapula, from 



226 



THE UPPER EXTREMITY. 
Fig. 97. 




The First ant) Second axd part of the Third Layers of Muscles of the 
Back," the First Layer beixg shovtx upox the Right, axd the Second ox the 
Left Side. — 1. The trapezius muscle. 2. The tendinous portion which, with a 
corresponding portion in the opposite muscle, forms the tendinous ellipse on the 
back of the neck. 3. The acromion process and spine of the scapula. 4. The 
latissimus dorsi muscle. 5. The deltoid. 6. The muscles of the dorsum of the 
scapula, infra-spinatus, teres minor, and teres major. 7. The external oblique 
muscle. 8. The gluteus medius. 9. The glutei maximi. 10. The levator anguli 
scapulae. 11. The rhomboideus minor. 12. The rhomboideus major. 13. The 
splenius capitis; the muscle immediately above, and overlaid by the splenius, is 
the complexus. 14. The splenius colli, only partially seen; the common origin of 
the splenius is seen attached to the spinous processes below the lower border of 
the rhomboideus major. 15. The vertebral aponeurosis. 16. The serratus posticus 
inferior. 17. The supra-spinatus muscle. 18. The infra-spinatus. 19. The teres 
minor muscle. 20. The teres major. 21. The long head of the triceps, passing be- 
tween the teres minor and major to the upper arm. 22. The serratus magnus, pro- 
ceeding forwards from its origin at the base of the scapula. 23. The internal 
oblique muscle. 



DISSECTION OF THE BACK. 227 

wliicli a few additional fibres sometimes arise. There is fre- 
quently a bursa between this part of the scapula and the 
muscle. It will be observed that the lower part of the 
muscle is inserted higher up than the upper part, resembling 
in this respect the pectoralis major. The use of this muscle 
is to depress the arm and shoulder, and draw the arm to 
the side of the thorax; it may also rotate the himierus in- 
wards. When the arm is elevated and fixed, it raises the 
lower ribs, thus assisting in respiration. 

Between the lower border of the trapezius and the upper 
margin of the latissimus dorsi, and behind the base of the 
scapula, is a triangular space, in which the rhomboideus 
major is seen. 

The trapezius is to be raised by detaching it from its origin, 
and reflecting it forwards. In doing this, the student must 
be careful that he does not at the same time raise the rhom- 
boidei muscles, which are situated immediately beneath the 
trapezius. 

In raising the latissimus dorsi it is difficult to avoid dis- 
secting up with it the tendon of the serratus posticus inferior. 
The connection of the tendon of the latissimus with the fascia 
lumborum at the posterior border of the external oblique 
should be observed. 

In raising the trapezius, the spinal accessory nerve. Fig. 63 
(i s), may be traced ramifying beneath, and sending branches 
to it. It gets beneath the muscle a short distance above its 
clavicular attachment. The attachvient of the omo-hyoideus 
to the superior costa of the scapula may be examined at the 
same time ; also the supra- scapular artery and ner^-e^ as they 
enter the supra spinata fossa. These were traced to this 
point while dissecting the supra-clavicular region in the neck. 

The transverse 1 mineral and j^osterior cervical arteries will 
be found beneath the trapezius and above the scapula. The 
first ascends, dividing into branches, which are distributed 
to the trapezius, levator anguli, scapulas, and splenius mus- 
cles, and anastomosing with the descending branch of the 
occipital. The other one passes backwards to near the pos- 
terior superior angle of the scapula, Avhcre it gets beneath 
tlie levator anguli scapula>, and descends along the base of 
the sca})ula and under the rhomboidoi muscles. It supplies 
the muscles iu that region, and anastomoses with the sub- 



228 THE UPPER EXTREMITY. 

scapular. The ramifications of this artery cannot be traced 
until the rhomboidei and levator anguli scapulge muscles 
have been dissected. 

It will be recollected, in dissecting off the trapezius and 
latissimus dorsi, that these muscles are perforated by the cu- 
taneous nerves of the back. If the student should wish to 
trace these nerves to their origin, he must dissect them out 
of the muscles as they are raised. 

The next muscles to be dissected are the rhomboidei major 
and minor, and the serrati postici superior and inferior. 

The Ehomboideus Major, Fig. 97 (12), arises from the 
spinous processes of the superior four or five dprsal ver- 
tebrae ; its fibres pass transversely across to the base of the 
scapula, into which they are inserted from the spine to the 
inferior angle. 

The Ehomboideus Minor, Fig. 97 (11), arises from the 
spinous processes of the inferior two or three* cervical verte- 
brae, and is inserted into that portion of the base of the scapula 
which corresponds to the spine. The two rhomboidei might 
be regarded as a single muscle, their separation being often 
very indistinct. They draw the scapula backwards and some- 
what upwards; the lower part acting alone will rotate the 
scapula, so as to depress the acromion process. 

In dissecting off the rhomboidei, a little care is necessary 
not to raise with them the following muscle, which is partially 
covered by them. 

The Serratus Posticus Superior arises from the spinous 
processes of the lower two or three cervical, and about the 
same number of the superior dorsal vertebrae ; it is inserted 
by three fleshy slips into the second, third, and fourth ribs. 
The action of this muscle is to elevate the ribs into which it 
is inserted. 

The Serratus Posticus Inferior, Fig. 97 (le), arises 
from the spinous processes of the two or three lower dorsal, 
and upper lumbar vertebrge, and is inserted into the four 
inferior ribs. Its tendinous origin is closely connected with 
the latissimus dorsi. Its action is either to depress the lower 
ribs, and thus assist in expiration, or to fix them, and thus 
assist the diaphragm, which is an inspiratory muscle. 

Extending from one serratus muscle to the other, is a 
well-marked aponeurosis; it is called the vertebral aponeurosis^ 



DISSECTION OF THE BACK. 229 

Fig. 97 (i 5). It is continuous below, witli tlie lumbar fascia, 
througli the inferior serratus and tendon of tbe latissimus 
dorsi. If pus be formed beneath the posterior layer of the 
fascia lumborum, there is nothing to prevent it from travelling 
upwards beneath this aponeurosis. 

In dissecting ofi' the serrati and rhomboid ei muscles, the 
student may notice the nerves which perforate them. 

The principal muscles of the back yet to be examined, 
have generally a longitudinal direction, and lie more or less 
parallel to each other. The student should read carefully a 
description of them before he attempts their dissection. 

The Spleistius, Fig. 97 (13), is commonly divided into the 
splenius colli, and sjolenius capitis. This division belongs 
rather to the upper than to the lower part of the muscle. 
The Splenius Colli arises from the spinous processes of the 
third, fourth, fifth, and sixth dorsal vertebrae. The Splenius 
Capitis arises from the spinous processes of the inferior cer- 
vical, and the first and second dorsal vertebrae. The former 
passes upwards, and is inserted by tendinous slips into the 
transverse processes of the superior two or three cervical 
vertebra, while the latter also goes upwards, and is inserted 
into the mastoid process of the temporal bone, where it is 
overlapped by the insertion of the sterno-cleido-mastoideus, 
and into the occipital bone below the upper transverse ridge. 

The actions of these two divisions of the splenius are in- 
dicated by their insertions. The splenius capitis draws the 
head backwards, and to one side. If the corresponding por- 
tion of the splenius on the opposite side acts at the same 
time, they will draw the head directly backwards. The sple- 
nius colli acts in the same manner on the neck. 

There is a triangular space betAVCcn the splcnii muscles of 
the two sides in the upper part of the neck, whicli is filled 
up with dense areolar tissue, and fat. The complcxus mus- 
cles are seen in this space. 

The Levator Angult Scapul.e, Fig. 97 (10), is situated 
outside of the splenius. It arises by te^idinous slips from the 
transverse processes of the superior three or four cervical 
vertebra). Its fibres pass obliquely downwards and back- 
wards, and arc inserted into the base of the scapula, between 
the spine and the superior angle. Its origin corresponds 
nearly with the insertion of the splenius colli. To dissect 
20 



230 THE UPPER EXTREMITY. 

it, the scapula should be depressed and carried forwards. 
The use of this muscle is to elevate the angle of the scapula, 
and thus depress the acromion process; acting with the tra- 
pezius, it assists in raising the shoulder. When the shoulder 
is fixed, it can bend the head back and to one side. 

When this muscle is detached i;iear its insertion, the student 
will be able to get a view of the serratus magnus from behind. 
By moving the scapula in different directions, the attach- 
ments and relations of this large muscle may be distinctly 
seen. 

The relations of the levator anguli scapulge to the posterior 
scalenus should, also, be noticed. It is important to keep in 
view the relations of the parts which are seen in the dissec- 
tion of the anterior portion of the neck, to those which are 
observed from behind. It should be borne in mind that the 
neck presents a lateral as well as an anterior smd posterior view. 

When the splenius is raised from its origin, and turned 
upwards, the four following muscles are brought into view in 
the neck. The splenius is perforated near its spinal attach- 
ment, by several nerves which may be noticed in raising it. 

The CoMPLEXUS, Fig. 98 (s), is a large, powerful muscle, 
with several tendinous intersections. It lies next to the 
spine, -and arises from the transverse processes of the upper 
three dorsal, and the oblique processes of the four lower cer- 
vical vertebras. Its fibres ascend and are inserted into the 
occipital bone between the two transverse ridges. When 
one acts alone, it rotates the head, or draws it back and to 
one side. When both of the complexus muscles act at the 
same time, they draw the head directly backwards. 

The Trachelo-Mastoideus, Fig. 98 (7), is a small muscle 
which arises from the transverse processes of the upper three 
or four dorsal, and the inferior three or four cervical verte- 
brae. Its fibres pass xipwards, and are inserted into the back 
part of the mastoid process. The dorsal portion of this 
muscle is frequently connected to the cervical by a small 
fasciculus. It assists other muscles in the movements of the 
head, as drawing it backwards, or backwards and to one 
side. 

The Transversalis Colli, Fig. 98 (9), is another small 
muscle, situated on the outside of the preceding. It arises 
by small slips from the transverse processes of the upper 



DISSECTION OF THE BACK. 



281 



five or six dorsal vertebrae, and passes upwards and out- 
wards, and is inserted into tlie transverse processes of the 
lower three or four cervical vertebrae. It assists in turning 
the neck to one side, or in drawing it backwards. 



The Ceevicalis Ascenbens, or 
(5), is placed on the outside of the 
arises^ by tendinous bands, from 
the upper four or five ribs, between 
their angles and tubercles, and 
passes upwards and outwards, and 
is inserted into the transverse pro- 
cesses of the fourth, fifth, and sixth 
cervical vertebrae. The action of 
this muscle is similar to the last, 
except that when the neck is fixed, 
it can assist in elevating the ribs. 

It is not always possible to 
make a clear dissection of the 
last three muscles, nor is it very 
important that the student should 
spend much time in attempting 
to do it. They seem to be a 
sort of a continuation upwards of 
the sacro-lumbalis and longissimus 
dorsi. 

At this stage of the dissection, the 
student will be able to take a gene- 
ral survey of the posterior spinal 
nerves in the deeper part of their 
course, and, also, of the arteries 
which go to the back. If he has 
not destroyed the nerves thus fiir 
in the dissection, he can now trace 
first, the Cervical. 



Descendens, Fig. 98 
transversalis colli. It 



Fig. 98. 




The rouRTn and fifth, and taut of the sixth layers of the IMuscles of the 
Back. — 1. Tho common origin of the erector spinas muscle. 2. The sacro-lumba- 
lis. 3. Tho longissimus dorsi. 4. Tho spinalis dorsi. 5. The corvicalis asoen- 
dens. 6. The transversalis colli. 7. Tho trachelo-niastoidous. S. Tlie coniplexus. 
9. Tho transversalis colli, showing its origin. 10. Tho somi-spinalis dorsi, 11. 
Tho semi-spinalis colli. 12. Tho rectus postiojis minor. i;>. Tho rectus posticus 
major. 14. Tho obliquus superior. 15. Tho obliquus inferior. 1(>. The multifidus 
spinal. 17. Tho levatoros costarum. 18. Intortransversales. 19. The quadratus 
lumborum. 



232 THE UPPER EXTEEillTY. 

The Occipitalis Major passes througli tlie complexus, 
beneatli ttMcIi he A\'ill find the j^osteinor cervical 2^lexiis^ which 
is formed by commimi eating branches from the upper three 
cervical nerves. The first cervical or suboccipital^ is quite 
small; it is situated above the obliquus inferior, and the 
second cervical below it. The third cervical is smaller than the 
second^ and the fourth is smaller than the third. 

The remaining cervical nerves increase in size from above 
downwards, and require no particular description. They 
may be traced to the intervertebral foramina as the deep 
muscles are dissected. 

The Posterior Dorsal Xeryes are twelve in number. 
They divide into external and internal branches. The external 
branches are found in the areolar interspace between the lon- 
gissimus dorsi and the sacro-lumbalis. The upper six are 
expended upon the muscles, while the lower six are distributed 
to the muscles and integument. The ecc/^ernaZ branches increase, 
while the internal diminish in size, from above downwards. 
The lovjer six become cutaneous, while the ujyjjer six are lost 
in the deep muscles of the spinal fossa. 

The Posterior Diyisiois"s of the Luj^ibar Keryes have 
the same general arrangement as the lower dorsal. 

The Posterior Sacral Nerves are five in number. The 
upper three divide into external and internal branches. The 
latter are small and muscular ; the former are quite large, 
and become cutaneous, receiving a branch from the last 

lumbar. 

The posterior cervical and transverse humeral arteries are 
described in the dissection of the neck. 

The Occipital Artery enters the posterior part of the 
neck beneath the sterno-cleido-mastoideus, passes transversely 
under the trachelo-mastoideus and splenius, and between the 
latter and the trapezius becomes subcutaneous, and ascends 
on the back of the head. Fig. 65 (] 4). In its course it sends 
small branches to the muscles with which it is in relation. It 
sends oft" quite a large branch, named the arteria pt'inceijs 
cervicis. beneath the splenius, which descends on the back of 
the neck, and anastomoses with branches of the subclavian 
artery. It also sends a small branch to the dura mater ; this 
passes through the jugular foramen. 



DISSECTION OF THE BACK. 233 

Tiie Yertebkal Artery sends small branclies in its course 
Tip tlie neck, to the deep muscles. 

The deep cervical branch of the subclavian sends branches 
to the muscles of the back. These anastomose with the 
occipital and vertebral arteries. 

The Intercostal Arteries send branches to that portion 
of the back which corresponds to the thorax. These branches 
supply the muscles as they pass througb them to reach the 
skin. They are named the dorsal branches of the intercostal 
arteries. 

The Lumbar Arteries send dorsal branches to the muscles 
and integument in the lumbar region. They correspond to 
the dorsal branches of the intercostals. The origin and 
course of these arteries are described elsewhere. 

The Sacro-Lumbalis, the Longissimus Dorsi, and the 
Spinalis Dorsi, Fig. 98 (i), may now be dissected. They 
consist of a single mass in the loins, and cannot be distinctly 
separated in that region. They constitute the erector spince. 
They arise in common from the dorsum of the sacrum, the 
sacro -iliac ligaments, from the spinous, transverse, and oblique 
processes of the lumbar vertebrae, and from the posterior 
third of the crest of the ilium. They are covered by a thick, 
strong tendon, from which, many of their fibres take their 
origin. At the upper part of the lumbar region these three 
muscles can be separated from each other. 

The Sacro-Lumbalis, Fig. 98 (2), is situated on the outer 
side. It passes upwards, dividing into tendons, which are 
attached to the ribs at their angles. When this muscle is 
separated from the longissimus dorsi, and raised from the 
ribs, six or eight muscular and tendinous slips will be ob- 
served. These constitute the accessorius ad sacro-litmbalein. 
They arise from the lower six or eight ribs, and join the ten- 
dons of the sacro-lumbalis. They vary in number and size. 
The sacro-lumbalis, besides supporting the spine, can depress 
the ribs, and thus act as a muscle of expiration. 

The Longissimus Dorsi, Fig. 98 (3), extends upwards on 
the inner side of the sacro-lumbalis, and is inserted into all 
the ribs except the upper two or throe, between their angles 
and tubercles, and also into the transverse processes of the 



234 THE UPPEE EXTEEMITY. 

dorsal vertebrae. It acts on the spine, and also on tlie ribs, 
as an expiratory muscle. 

The Spinalis Doesi, Fig. 98 (4), lies on the inner side of 
the last muscle, with which it is usually more or less blended. 
It arises from the spinous processes of the lower two or three 
dorsal vertebrse, and about the same number of lumbar ver- 
tebrae ; it is inserted into the upper dorsal. 

The QuADEATUS LuMBOEUM, Fig. 98 (19), should now be 
dissected, on one side at least, so that the relations of the 
fascia lumborum may be studied in connection with the mus- 
cles of the back. It may also be examined with the muscles in 
the posterior part of the abdominal cavity. It is situated 
between the erector spinse and the cavity of the abdomen. It 
arises from the posterior part of the crest of the ilium and 
the ilio-lumbar ligament. The fibres pass upwards, and are 
inserted into the transverse processes of the upper four, lumbar 
and the last dorsal vertebrae, and also into the vertebral half 
of the last rib. An additional set of fibres usually arise from 
the transverse processes of the lower two or three lumbar 
vertebrae, pass obliquely upwards, and are inserted into the 
last rib. The action of this muscle is to depress or fix the 
last rib, to bend the spine to one side, or to assist in keeping 
it erect. 

The Fascia Lumboeum is attached by three laminae to the 
vertebral column. The posterior lamina is blended with the 
tendon of the latissimus dorsi and serratus posticus inferior, 
and is consequently connected to the spinous processes. The 
middle layer is attached to the ends of the transverse pro- 
cesses ; while the anterior layer is attached to the bases of the 
transverse processes of the lumbar vertebrae, to the lower rib, 
and to the ligamentum arcuatum. The internal oblique and 
transversalis muscles are connected to the vertebral column 
through the medium of this fascia. The space betAveen 
the middle and anterior laminae is wholly occupied by the 
quadratus lumborum muscle. If pus should form in this 
space, it might pass upwards or downwards as far as the 
attachments of this muscle. If pus should collect in the 
space between the middle and posterior layers, it might 
travel upwards or downwards along the erector spinae 
which occupies this space. The difference between the 



DISSECTION OF THE BACK. 235 

location of a kimbar and psoas abscess will be learned in 
connection with, the psoas fascia. 

The relations of the colon to the muscles and fascia in the 
lumbar region should be studied. It will be seen that the 
colon can be reached in this region by simply dividing the 
three laminae of the fascia lumborum along the external bor- 
ders of the sacro-lumbalis and quadratus Limborum. The 
relation of the kidney to the muscles in this region, is also 
deserving of notice with reference to nephritic abscesses. 

The following muscles may now be exposed, by removing 
those last dissected : — 

The Semi-Spinalis Doesi and Colli, Fig. 98 (lo, n), 
might with propriety be considered a single muscle. They 
present the same arrangement in regard to their origin and 
insertion, and have a similar function. 

The semi-spinalis colli, arises from the transverse processes 
of the upper five or six dorsal vertebrae, and passes upwards 
and is inserted into the spinous processes of the second, third, 
fourth, and fifth cervical vertebrae. 

The semi-spinalis dor si arises from the transverse processes 
of all the dorsal vertebrse below the fifth, excepting the last, 
and passes upwards and is inserted into the spinous processes 
of the lower two cervical, and the upper three or four dorsal 
vertebra. These muscles co-operate with the erector spinae. 

Situated beneath the two last muscles are a series of small 
muscles, called, altogether, the multifidus SPiNiE. They 
extend between the spinous and transverse processes. The 
upper one commences at the spinous process of the second 
cervical vertebra, and is inserted into the transverse process 
of the third. The last one extends from the spinous process 
of the last lumbar vertebra to the sacrum. The same muscle 
may extend over one or two intermediate vertebras. The 
action of these is nearly the same as the last. 

The Levatores Costarum, Fig. 98 (i 7), maybe examined 
at the present time, although they are frequently considered 
as belonging to the external intercostal muscles. They con- 
sist of a series of small fan-shaped muscles, which arise from 
the transverse processes, commencing ^yith the' last cervical, 
and extending to the last dorsal. They pass do\vnAvards and 
outwards, and are inserted into the ribs between their angles 
and tubercles. They increase in length from above down- 



236 THE UPPEE EXTEEMITY. 

wards. Some of tlie lower m-Qscles pass in part over the 
first rib below their origin, to be attached to the next one; 
these have been called the levatores longiores costarum. 

The Interspixales extend between the spinous processes. 
Between the dorsal vertebrae they can hardly be said to exist, 
and are very small in the lumbar region. In the neck, they 
are found in pairs, corresponding to the bifid condition of 
the spinous processes. Some of them pass over one or more 
vertebrae, and are called supi^a-spinous. There is none be- 
tween the first two vertebrae. 

The IxTERTRANSVERSALES, Fig. 98 (i s), are a series of short 
muscles, extending between the transverse processes. In the 
neck, they consist of two fasciculi, an anterior and posterior. 
In the dorsal region they are generally wanting, excepting 
between the last two vertebrae. In the lumbar region they 
are smaller than in the neck. They support the spine, and 
bend it to one side. 

Between the occiput and the upper cervical vertebrae are 
several small muscles, which are worthy of more attention 
than some of the preceding. 

They are deep-seated, and, to dissect them, the position of 
the head must be changed, so as to render them tense. 

This group of muscles is separated from the complexus by 
an aponeurosis and dense areolar tissue. They consist of two 
obliqui and two recti, on each side; between these "v^dll be 
found a triangular space, occupied by fat and areolar tissue, 
and containing, also, the posterior division of the suboccipital 
nerve, which is distributed to those muscles, a plexus of veins, 
and the vertebral artery. 

The Eectus Capitis Posticus Major, Fig. 98 (i s), arises 
from the spinous process of the second vertebra, passes up- 
wards, and is inserted into the inferior transverse ridge of 
the occipital bone. It is of a triangular shape, being broad 
above and narrow below. It is covered by the complexus, 
and the superior oblique partly overlaps its insertion. 

The Eectus Capitis Posticus Mikor, Fig. 98 (i 2), is a very 

small muscle, situated beneath the major. It arises from the 
spinous process of the first cervical vertebra, and is inserted 
into the occipital bone, between the inferior transverse ridge 
and the occipital foramen. The small recti muscles are 
situated nearer to the median fine than the large. The recti 



DISSECTION OF THE BACK. 237 

muscles draw the head backwards, or to one side. The large 
recti may assist in rotating it, or moving it on the axis. 

The Obliquus Capitis Infeeioe, Fig. 98 (i 5), arises from 
the spinous process of the second vertebra, goes upwards and 
outwards, and is inserted into the transverse process of the 
atlas. It moves the atlas round the odontoid process, and 
thus assists in rotating the head. 

The Obliquus Capitis Supeeioe, Fig. 98 (14), arises from 
the transverse process of the atlas, and passes upwards and 
inwards, and is inserted into the occipital bone just above the 
insertion of the rectus major, which is partly covered by it. 
The upper part of this muscle is broad and aponeurotic. It 
bends the head backwards and to one side. 

After the muscles on the back of the neck have been dis- 
sected, the vertebral artery may be examined in its cou.rse 
through the transverse processes, and as it enters the foramen 
occipitale. It is accompanied by the vertebral vein. 

The great number of muscles on the back, with their nu- 
merous attachments, renders this part of the i)ody somewhat 
difficult of dissection and study. Few students have the time 
and patience to learn all these muscles and their attachments, 
and, when it is done, the knowledge thus acquired cannot 
long be retained. Yet the dissection of the back should not 
be neglected; it should receive a portion of the time and 
attention of every student. 

Instead of attempting to recollect the exact origin and in- 
sertion of each muscle, or any mere arbitrary division based 
upon their arrangement in layers or strata, he should rather 
endeavor to fix them in his mind according to their individual 
or combined action. As, for example, he should arrange and 
classify in his own mind all those muscles which act directly 
or indirectly on the shoulder, and through the shoulder on 
the arm or on the walls of the thorax, as in respiration. In 
this way he will learn what muscles are at fault in displace- 
ments of the scapula, or in curvatures of the spine depending on 
a loss of antagonism in the muscles of the tAvo sides, or of tone 
in those of both sides. All tlic muscles concerned in support- 
ing or moving the head should be grouped together as acting 
in unison, and also those which act on the vertebral colunni, 
but not as acting on separate vertebras so much as on its 
diifcrcnt sections. When the muscles of the back are studied 



238 THE UPPER EXTREMITY. 

in this way, classified according to their functions, they become 
an interesting portion of the animal economy. A knowledge 
of the exact relations of the muscles of the back to each other 
is not so important as in many other parts of the body, where 
there are large vessels and nerves, or other important organs, 
in relation with them. 



Sect. III. — Dissection of the Shoulder. 

In detaching the upper extremity from the trunk, it is de- 
sirable to disarticulate the clavicle from the sternum; but it 
frequently happens that the dissection of the head and neck 
is not sufficiently advanced to allow of this, at least on both 
sides, without injuring those parts. In this case, the clavicle 
should be left attached to the trunk while the scapula is re- 
moved with the arm, by separating it at the acromio-clavicu- 
lar articulation. Even the removal of the scapula will inter- 
fere more or less with the lower part of the side of the neck, 
but not materially, if the back of the neck has been fully 
dissected. The vessels and nerves in the axilla should be 
tied together, so that they can be made tense by fastening 
them to something with hooks or twine. 

In dissecting the arm, no specific rules can be laid down in 
regard to the position. The student must select such position 
as will put the muscle or muscles which he is dissecting on 
the stretch, or allow him to trace with the greatest facility the 
vessels and nerves as he proceeds in his dissection. 

~ The anterior part of the Deltoid was, Fig. 90 (s), exposed 
with the clavicular portion of the pectoralis major ; the re- 
mainder of it, Fig. 100 (is), may now be dissected by con- 
tinuing the dissection from before backwards. The skin 
may be raised first, so as to examine the deltoid fascia and 
to trace the supra-acromial hranches^ Fig. 103 (i), from the 
cervical plexus of nerves, and cutaneous hra7iches (.2) from 
the circumflex nerve which is reflected over the posterior 
margin of the muscle; or the student may remove the skin 
and fascia from the muscle at the same time. This muscle 
is composed of very large fasciculi, each one of which seems 
to be a small muscle of itself 

It arises, tendinous and fleshy, from the outer third of the 
clavicle, from the acromion process and spine of the scapula; 



DISSECTION" OF THE SHOULDER. 



239 



Fig. 99. 




its fibres converge to form a short, thick tendon, whicli is 
iiiserted into the deltoid ridge of the humerus. This muscle 
may be divided into anterior, middle, 
and posterior portions. It will be seen, 
from the origin and insertion of the 
deltoid, that it is of a triangular form, 
and covers all the outer part of the 
shoulder-joint. Its action is to raise 
the arm, and to keep the head of the 
humerus applied to the glenoid cavity. 
If the posterior fibres act alone, they 
will draw the arm upwards and back- 
wards, while the anterior fibres, acting 
alone, will draw it upwards and for- 
wards. Its origin corresponds to the 
insertion of the trapezius. 

This muscle should be raised by 
detaching it from its origin and re- 
flecting it downwards. In dissecting 
it up from the humerus, the anterior 
and posterior circumflex arteries and the 
circumflex nerve will be observed enter- 
ing its under surface. It will be seen 
that a blow over the deltoid might, by 
injuring the circumflex nerve, paralyze 
this muscle. There is also to be noticed 
a large bursa between it and the upper 

and outer part of the humerus. Its relations to the shoulder- 
joint and the parts around it are deserving of special atten- 
tion. It will be observed that its under surface is more 
tendinous than the outer, and that many of the muscular fas- 
ciculi terminate in a tendinous structure some distance from 
the point of insertion. 

The deltoid muscle is to be preserved, in order to replace 
it after the parts which are covered by it have been dissected. 
It is only in this way that its relations can be properly un- 
derstood. 

The SuprA-Spinatus, Fig. 100 (2), occupies the supra-spi- 
nata fossa. It is covered by the trapezius, and by a thick, 
dense aponeurosis, named the supraspinous fascia . This fascia 
is attached to the margins of the Ibssa, and sends a process for- 



A View op the Deltoid 
Muscle. — 1. Clavicle. 2, 3, 
4. Origin of the deltoid from 
the clavicle, acromion, and 
spine of the scapula. 5, Body 
of the scapula. 6. Middle of 
the deltoid, showing the fasci- 
culated character of its fibres. 
7. Its insertion. 8. Shaft of 
the OS humeri. 



240 THE UPPER EXTEEMITY. 

wards, to be lost in the tendon of tlie supra-spinatus muscle. 
Eemoving this fascia, the muscle will be exposed. It arises 
from the surface of the whole fossa, except the anterior part, 
and also from the under surface of the fascia, posteriorly. It 
passes beneath the acromion process, and ends in a tendon 
which is inserted into the upper part of the great tuberosity 
of the humerus. 

Its tendon is blended with the capsular ligament of the 
joint, over which it passes. There is a great deal of loose 
areolar tissue situated around this muscle, where it passes 
under the acromion process and the coraco -acromial ligament. 
It assists the deltoid in raisins; the arm, and, when it is raised, 
prevents the head of the humerus from being displaced into 

Fig. 100. 




A Posterior Vietv of the MrscLES or the SnorLDER, "ut:th the Deltoid. — 
1. Acromion scapulte. 2. Supra-spinatus muscle. 3. Spine of the scapula. 4. 
Posterior portion of the origin of the deltoid. 5. Infra-spinatus muscle. 6. Teres 
major. 7. Teres minor. 8. Long head of the triceps extensor. 9. Its second head. 
10. The shaft of the os humeri. 11. Brachialis anticus. 12. Insertion of the 
deltoid. 13. Its middle portion forming the round part of the shoulder. 

the axilla, by keeping it firmly applied to the glenoid cavity ; 
it also draws the capsular ligament from beneath the acromion 
process, when the head of the humerus is pressed against it. 
In raising the supra-spinatus, the supra-scapular artery and 
nerve are to be traced. They are continued into the infra- 
spinata fossa by passing under the acromion process, where 
they will be met with when the infra-spinatus muscle is dis- 
sected. The nerve usually passes through the coracoid notch, 
to enter the supra-spinata fossa, while the artery generally 
passes over the ligament which subtends this notch and con- 



DISSECTION OF THE SHOULDER. 



241 



verts it into a foramen. The ligament is named the coracoid 
or supra-scapular ligament. 

The two following muscles are situated on the dorsum of 
the scapula, below the spine : the infra-spinatus, and teres 
minor. Besides the skin and subcutaneous fascia, they are 
covered with the infra-spinous fascia^ or aponeurosis. This 
fascia is attached to the margins of the infra-spinata fossa, 
and, at the posterior border of the deltoid, divides into two 
layers, one of which is continuous with the deltoid fascia over 
that muscle, while the other passes beneath it, and becomes 
continuous with the brachial fascia. 

The Infra-Spinatus Muscle, Fig. 101 (5, 13), arises from 
nearly the whole of the infra-spinata fossa, and posteriorly 

Fig. lOL 




A Posterior View of the Muscles of the Shoulder which strengthen the 
Articulation. — 1. Acromion scapulEe. 2. Supra-spinatus muscle. 3, Upper angle 
of the scapula. 4. Spine of the scapula. 6. Origin of the infra-spinatus muscle. 
6, 7. Origin of the teres major. 8. Origin of the teres minor. 9. Insertion of the 
teres major. 10. Shaft of the os humeri. 11. Lower part of the capsular ligament. 
12. Insertion of the teres minor. 13. Insertion of the infra-spinatus. 

from the infra-spinous fascia. The fibres which arise from 
the spine of the scapula overlap those below, and they all 
converge to form a short tendon, which is inserted into the 
great tuberosity of the humerus, just below the insertion of 
the supra-spinatus, with which it is connected. Its tendon is 
blended with the capsular ligament. It can assist the deltoid 
in raising the arm, and drawing it backwards; or it can rotate 
the humerus outwards; it may also withdraw the capsuhxr 
ligament from the joint, or, when the arm is raised, depress 
the head of the humerus. 
21 



242 THE UPPEK EXTEEMITY. 

The Teees Minok, Fig. 101 (s, 1 2), is quite a small muscle, 
and might be regarded as a part of the infra-spinatus. It 
arises from a depression on the dorsum of the scapula, near 
the inferior border, commencing about an inch from the pos- 
terior inferior angle, and from the infra-spinous fascia. It is 
inserted into the great tuberosity of the humerus, just below 
the insertion of the infra-spinatus. Its action is the same as 
that of the preceding muscle, with which it is sometimes in- 
separably connected. 

The Teees Majoe, Fig. 101 (9), was exposed, from before, 
in the dissection of the axilla ; it may now be examined from 
behind. It arises from a rough surface on the dorsum of the 
scapula, near the inferior angle, and from the fascia covering 
it. Its direction, insertion, and relations to the latissimus 
dorsi, have been noticed. 

The long head of the Teiceps Extensoe Cubiti, Fig. 100 
(s), is necessarily brought into view in dissecting the teres 
major. It may be noticed at the present time as one of the 
muscles connected to the scapula, and as forming a part of 
the anatomy of the region now being examined. In raising 
the infra-spinatus and teres minor, the suj^ra-scapular artery 
and nerve are to be traced from beneath the acromion process. 
The dorsal branch of the subscapular artery, by passing over 
the inferior border of the scapula and beneath the teres minor, 
also enters this fossa. These arteries anastomose freely with 
each other, and also with the transverse humeral, along the 
base of the scapula. Articular branches to the shoulder -joint, 
are derived from both the supra- scapular artery and nerve. 

The student should now review the parts which have been 
dissected about the shoulder. The muscles which have been 
raised should be replaced and their relations and functions 
carefully noted without the aid of a book. It will be observed 
that the deltoid, when placed in situ^ covers the following 
parts : The outer portion of the shoulder -joint, and the upper 
part of the humerus, including its two tuberosities ; the bi- 
cipital groove, containing the long head of the biceps, and 
anterior to this the coracoid process, and, to some extent, the 
muscles attached to it; and posteriorly the infra-spinatus, 
and teres, minor and major, near their insertions. 

He is now prepared to understand the position of the head 



DISSECTION OF THE SHOULDER. 



243 



of tlie humerus when luxated either backwards, downwards, 
or forwards, and the new relations it acquires in these dis- 
placements to the surrounding parts. He can readily see for 
himself what muscles will be relaxed, and what will be put 
on the stretch when the head of the humerus is made, by 
displacement, to occupy a new position. He can now note 
the effect of the contraction of the deltoid in producing dis- 
placement of the acromion process when broken off, or that 
of the trapezius in preventing displacement ; also the effect 
of the contraction of the muscles attached to the coracoid 
process when that is fractured. These practical points should 
be impressed on the mind while the parts involved are before 
him. 

The shoulder-joint and ligaments around it may now be 
examined. This can be done 
without interfering with any- Fig. 102. 

thing yet to be dissected on the 
arm. 



The clavicle and acromion pro- 
cess are connected by ligament- 
ous fibres which surround the 
articulation, forming a sort of 
fibrous capsule. As the fibres 
are rnore numerous above and 
below the joint, they are some- 
times spoken of as the Supeeior 
and Inferior Acromio-Clavic- 
ULAR Ligaments, Fig. 102 (i). 
This joint sometimes contains 
two synovial membranes which 
are separated by an interarticular 
fibro-cartilage. This fibro-carti- 
laginous septum, however, is 




The Ligaments op the Scapula 

AND SlIOULDEH-JoiNT. — 1. The 



sometimes imperfect, Avhen there penor acromio-clavicular ligament. 

will be only one synovial mem- 
brane in the joint. The articular 
surfaces of this joint are very 
small, rendering it difficult to 
keep the acromial extremity of 



The coraco-clavieuhrr ligament; 
this aspect of the ligament is named 
trapezoid. 3. The coraco-aeromial 
ligament. 4. The coracoid ligament. 
5. The capsular ligament. 6. The 
coraco-humeral ligament. 7. The 
long tendon of the biceps issuing 

the clavicle in its proper place IrringthXipUai'S"-'' "' 
after it has been luxated. 



244 THE UPPEK EXTREMITY. 

The clavicle is connected to tlie coracoid process by two 
ligamentous fasciculi; the posterior and internal is named 
the CoKoiD, and the anterior the Trapezoid Ligament. 
They form really but a single ligament, the coraco-clavicular^ 
Fig. 102 (2). They extend from the coracoid process to a 
rough protuberance on the under surface of the clavicle, and 
about an inch from its acromial extremity. In front they 
are separated by a space which is filled up with areolar tissue, 
but posteriorly they appear as a single ligament. 

Sometimes quite a perfect joint is found between the cora- 
coid process and the clavicle which allows the latter to move 
on the former. 

The Coracoid Ligament, Fig.- 102 (4), subtends the coracoid 
notch, converting it into a foramen. 

The Triangular, or Coraco-Acromial Ligament, Fig. 
103 (3), extends from the coracoid process to the acromion. 
Its coracoid attachment is much broader than the acromial. 
It fills up, in part, the notch between these processes and pre- 
vents the head of the humerus from being forced upwards 
between them. 

The CoRACo-HuMERAL Ligament, Fig. 102 (e), extends 
from the coracoid process to the great tuberosity of the 
humerus. It may be considered as a part of the capsular 
ligament. 

The Capsular Ligament, Fig. 102 (5), of the shoulder- 
joint is attached above to the neck of the scapula, and below 
to the anatomical neck of the humerus. Its length allows the 
head of the humerus to be separated a short distance from the 
scapula. Its strength is greatly increased by its connection 
with the tendons of the supra-spinatus, infra-spinatus, teres 
minor, and subscapularis muscles. These tendons, however, 
do not add to the strength of the lower part of the ligament, 
and hence there is a predisposition to luxation of the head of 
the humerus downwards. 

When the capsule is partly divided, the tendon of the long 
head of the biceps flexor cubiti, Fig. 102 (7), will be seen 
passing over the upper part of the articular cavity. It is 
inside of the ligament, but external to the synovial mem- 
brane, which is reflected around it and prolonged an inch or 
more downwards in the bicipital groove, forming a pouch, 



DISSECTION OF THE AEM. 245 

wMcli communicates with tlie cavity of the joint. The ex- 
tent of the synovial membrane is worthy of notice, as it is 
reflected over the head of the humerus, the internal surface 
of the capsular ligament, including a portion of each of the 
tendons connected with it, and the glenoid cavity. "While it 
frequently communicates with the bursse beneath the tendons 
of the infra-spinatus and subscapularis. 

The GrLENOiD LiG-AMENT surrounds the margin of the glen- 
oid cavity, and deepens and increases the extent of its ar- 
ticulating surface. In structure it is fibro-cartilaginous, the 
cartilage predominating where it is attached to the bone and 
connected with the articular cartilage. The tendon of the 
long head of the biceps appears to arise, by two fasciculi, 
from the upper part of this ligament. 



Sect. TV. — Dissection" of the Arm. 

Having finished the examination of the shoulder, the next 
stage in the dissection will embrace the arm and a part of the 
forearm. An incision may be made through the skin along 
the forepart of the arm, and in front of the elbow-joint, ex- 
tending it down four or five inches on the forearm. There 
is no necessity for making any transverse incision in the skin 
at present ; if it be done, however, care must be taken not to 
cut the cutaneous vessels and nerves. 

After reflecting the skin from the anterior part of the arm 
and bend of the arm, the following vessels and nerves are to 
be traced in the superficial fascia, or subcutaneous areolar 
tissue. As they have been, for the most part, already exposed 
in the axilla, the student will have no difiiculty in following 
them : — ■ 

The Cephalic Yein, Fig. 94 (lo), will be found passing 
down the outer side of the arm. Just above the bend it re- 
ceives a large branch, the Median Cephalic, Fig. 94 (is), 
which joins it on its ulnar side. The cephalic now becomes 
the radial, and may be traced as far as the skin has been 
raised, taking care not to destroy filaments of the external 
cutaneous nerve, which has now become subcutaneous. The 
Median Cephalic may also bo traced to its commencement 
in the median vein. 

2P- 



246 THE UPPER EXTREMITY. 

The Basilic Vein, Fig. 94 (4), will be foiind passing down 
the inner part of the arm. It is much larger than the 
cephalic; near the bend of the arm it receives the isiedian 
BASILIC, Fig. 96(5), which joins it from the radial side. The 
basilic now becomes the ulnar vein, and is to be traced down 
as far as the cephalic was dissected. The median basilic is 
to be followed to its termination in the median vein, which 
may now be exposed for two or three inches. 

The Mediax Yeix, Fig. 94 (4), will be seen bifurcating 
to form the median basilic and the median cephalic. The 
median vein, near its bifurcation, gives off a short trunk, 
which dips down to join the deep veins ; this is named the 
Yexa Commuxicaxs, Fig. 94 (5). 

The internal cutaneous, the lesser internal cutaneous, and 
the intercosto-humeral nerves, should be dissected with the 
basilic vein. These nerves are easily followed by making 
them slightly tense, when their course will readily be seen 
under the fascia. 

The IxTERXAL CuTAXEOus Xerve, Fig. 103 (6, 7), in the 
lower part of the arm, divides into an external and internal 
branch. The external di^dsion passes over the median basilic 
vein, and descends on the front of the forearm; while the 
internal passes over the inner part of the elbow, and winds 
round to the back part of the forearm. 

The Lesser Ixterxal Cutaxeous, Fig. 103 (9), descends 
on the inner aspect of the arm to the space between the in- 
ternal condyle and the olecranon process, sending off fila- 
ments in its course to the skin on the posterior part of the 
arm, and for a short distance below the elbow. Xear the 
elbow, it gives off a filament to anastomose with the internal 
cutaneous. The intercosto-humeral^ Fig. 103 (1 0), is lost in the 
skin on the upper and back part of the arm. 

On the outside of the arm are usually two cutaneous 
Irranclies^ Fig. 103 (3) and Fig. 104 (5) from the musculo-spiral 
nerve. One of these generally accompanies the cephalic vein 
to the bend of the arm ; the other descends more externally, 
and, passing over the elbow-joint, supplies filamentsto the 
skin on the back and upper part of the forearm. 

The External or Musculo-Cutaxeous, Fig. 103 (4), be- 
comes superficial just above the bend of the arm, and outside 
of the tendon of the biceps flexor muscle. A large branch 



DISSECTION OF THE ARM. 



247 



generally passes behind the median cephalic vein, which may 
be used as a guide for finding it. 

Fig. 103. Fig. 104. 



10 



Plan of the Cutaneous Netives on 
THE FRONT OP THE Arm. — 1. Supra-cla- 
vicular nerves. 2. Branches of the cir- 
cumflex nerve. 3. External cutaneous 
(upper branch) of the nuisculo-spiral 
nerve. 4. Musculo-cutaneous. 6. Branch 
of u hi ar nerve. 6. Internal cutaneous : 
external branch. 7. Inner branchy of 
that nerve. 8. Offset to the upper arm 
from same. 9. Lesser internal cutane- 
ous. 10. Intercosto-humeral norvo. 



Plan op the Cutaneous Nerves op 

THE back of the ArM AND FoREARSf. 

— 1. Supra-acroniial branches of tho 
cervical plexus. 2. Cutaneous branches 
of the circumflex nerve. 3. Internal 
cutaneous of the rausculo-spiral. 4. 
Intercosto-humeral branches. 5. Ex- 
ternal cutaneoxis (inferior) of the mus- 
culo-spiral. 6. Ending of the nerve of 
Wrisberg. 7. Part of tlie internal cuta- 
neous for the back of the forearm. 8. 
Offset from the dorsal branch of tho 
ulnar nerve. 9. Radial nerve. 10. 
Branch of the musculu-cutaueous for tho 
back of the forearm. 



The arrangements of the veins in the bend of tho arm vary 
so much, that it is impossible to give a description which 



248 



THE UPPER EXTREMITY. 



will apply to any considerable number of cases. The two 
median veins particularly, are very irregular. The cutane- 

Fig. 105. 



1. The radial vein. 2. The cephalic vein. 3. The 
anterior ulnar vein. 4. The posterior ulnar vein. 
5. The common ulnar vein. 6. The basilic vein. 7. 
The point at which the basilic vein pierces the fascia. 
8. The median vein. 9. The communication between 
the deep veins of the forearm and the median. 10. 
The median cephalic vein. 11. The median basilic 
vein. 12. A slight convexity of the deep fascia, formed 
by the brachial artery. 13. The slip of fascia derived 
from the tendon of the biceps, which separates the 
median basilic vein from the brachial artery. 14. 
The external cutaneous nerve, piercing the fascia, 
and dividing into two branches, which pass behind 
the median cephalic vein. 15. The internal cutane- 
ous nerve, dividing into branches, which pass in 
front of the median basilic vein. 16. The nerve of 
Wrisberg. 17. The spiral cutaneous nerve, branch 
of the musculo-spiral nerve. 



ous nerves, on the contrary, usually have nearly the same 
position ; so that they may be avoided by selecting a proper 
place for opening a vein. The place selected is more import- 
ant to be considered in bleeding than any particular vein. 

As the internal cutaneous nerve is more superficial, usually 
passing in front, Fig. 105 (i 2), of the median basilic, than the 
external cutaneous, which is commonly situated behind the 
median cephalic, Fig. 105 (14), the outer part of the bend of 
the arm should be selected for opening a vein. The lymph- 
atics, also, are less numerous here than in the middle or inner 
part of this region, and are not so liable to be wounded. The 
relations of the veins in the bend of the arm to the median 
nerve and brachial artery, will be observed at another time. 

The Yena Communicans, Fig. 99 (15) and Fig. 105 (9), 
may now be examined ; so that the superficial fascia can be 
divided and reflected laterally from the median line in the 
same manner as the skin. This is a short vein, which 




DISSECTION OF THE ARM. 



249 



'« 



establishes a direct commimication ^^g- 1^^- 

between the superficial and deep- 
seated veins. It has no valves ; and 
hence, in varicose aneurism, or aneu- 
rismal varix, it allows the blood to 
pass readily from one set of veins to 
the other. 

The Superficial Lymphatics 
accompany the veins, especially the 
basilic. A single lymphatic gland 
is placed in front of the inner con- 
dyle. The lymphatics terminate in 
the axillary glands. 

The Deep Fascia, or Brachial 
Aponeurosis, Fig. 106, lies directly 
beneath the superficial fascia. It 
consists of fibres, running, some in a 
longitudinal, some in a spiral, and 
others in a circular direction. It 
increases in thickness and strength 
from above downwards. Above, it 
is connected to the pectoral, deltoid, 
infra-spinous, and axillary fasciae, also 
to the tendons of several of the mus- 
cles about the shoulder; some of 
which are capable of rendering it 
more or less tense when they con- 
tract. It is connected to the humerus 
by two processes, or septa, an exter- 
nal and an internal. 

The external is attached to the 
outer part of the humerus, extending 
from the outside of the deltoid ridge 
to the external condyle, separating the 
triceps extensor from the brachialis 
anticus muscle, and, at the same 
time, giving origin to many fibres 
of these muscles, especially at the 

a View of the Fascia Brachialis m its whole extent. — 1. Portion covering 
the deltoid muscle. 2. Portion covering the upper part of the biceps. 3. Portion 
covering the coraco-bracbialis. 4. Portion covering the lower part of the biceps. 
5. Tendon of the biceps. 6. Opening for the vein. 7. Aponeurosis .is strengthened 
by the expansion from the tendon of the biceps. S. Fascia over tlie tloxor sublimis. 
9. Fascia over the flexor carpi radialis. 10. Commencement of the palmar fascia. 



^JiTH, 



250 



THE UPPER EXTREMITY. 



lower part of tlie arm. The musculo -spiral nerve and supe- 
rior profunda artery perforate this intermuscular septum. 

The internal septum commences at the insertion of the teres 
major and latissimus dorsi, and extends to the inner condyle 
of the humerus. It is narrower above than below. The 
brachiaiis anticus and triceps extensor 
cubiti muscles are intimately connected 
with it in the lower part of the arm. It 
is perforated by the ulnar nerve. 

The brachial aponeurosis furnishes 
sheaths for the muscles of the arm, and 
is connected to the sheaths of the bra- 
chial vessels and nerves. Besides its 
attachment to prominent points about 
the elbow, it is continued into the apo- 
neurosis of the forearm. It binds down 
the muscles of the arm, gives attachment 
to muscular fibres, and serves to protect 
the brachial vessels and nerves. 

The Biceps Flexor Cubiti Muscle, 
Fig. 107 (i 5), may now be exposed by 
dividing the aponeurosis along the mid- 
dle of the forepart of the arm, and re- 
flecting it to each side. The heads of 
this muscle arise^ as has been seen, the 
long one from the upper part of the 
glenoid cavity, and the short from 
the coracoid process, in common with 
the coraco-brachialis, from which it 
cannot be separated without making 
an arbitrary division. The heads unite 
just above the middle of the humerus, 
to form quite a large, prominent belly, 
which ends in a flat tendon, a short dis- 

A View op- the Muscles on the Front op the Arm. — 1. Clavicle. 2. Coracoid 
process and origin of the short head of the biceps. 3. Acromion scapula?. 4. Head 
of the OS humeri. 5. Tendon of the biceps muscle in the bicipital groove. 6. Co- 
raco-humeral dissected off. 7. Cut portion of the pectoralis major. 8. Long 
head of the biceps. 9. Insertion of the deltoid. 10. Cut portion of the tendinous 
insertion of the pectoralis minor. 11. Coraco-brachialis. 12. Short head of the 
biceps. 13. Latissimus dorsi. 14. Inner portion of the triceps. 15. Body of the 
biceps. 16. Outer portion of the triceps. 17. Brachiaiis anticus. 18. Origin of 
the flexor muscles. 19. Brachiaiis anticus near its insertion. 20. Tendon of the 
biceps. 21. Fasciculus from the biceps tendon to the brachial aponeurosis. 22. 
Flexor carpi radialis. 23. Palmaris longus. 24. Supinator radii longus. 




DISSECTION" OF THE AEM. 



251 



tance above tlie elbow-joint. Tbe short head is muscular from 
near its origin ; while the long one continues tendinous to 
near their junction. The latter 
is bound down in the bicipital ^ig- 1^8. 

groove by transverse fibres, 
which are said to be torn some- 
times, allowing a displacement 
of this tendon. The biceps 
is inserted into the tubercle of 
the radius. 

From its tendon proceeds 
an aponeurotic expansion. 
Fig. 107 (21), which passes in- 
wards and downwards across 
the elbow-joint, and joins the 
aponeurosis of the forearm, 
which, bj means of this con- 
nection, is made tense by the 
contraction of the biceps mus- 
cle. This fibrous expansion 
is liable to be wounded in 
bleeding at the bend of the 
arm, which may be followed 
by lameness in the limb for a 
few days. 

This muscle flexes the fore- 
arm on the arm, and renders 
its aponeurosis tense. It can 
also rotate the radius out- 
wards, and assist in abduct- 
ing the arm, as it is attached 
above the shoulder-joint. The 
action of the biceps on the 
upper part of the radius, 
when a fracture occurs just 
below the tubercle, is to ro- 
tate the upper fragment out- 
wards, and draw it upwards, 

A Plan of the Nerves op the Arm.— a. Axillary artery, b. Bniebial artery. 
Nerves: 2. Supra-senpular. 3. Subscapular. 4. Internal cutaneous, b. Musculo- 
cutaneous G. Circumflex. 7. Ulnar. 8. Superficial branch of the same to the 
hand. 12. Median. KJ. Anterior interosseous. 15. Museulo-suiral. 10. Radial. 
17. Posterior interosseous. 




252 THE UPPER EXTREMITY. 

as in flexion of tlie forearm. The dissection of tlie deep part 
of tlie tendon of the biceps may be postponed until the vessels 
in this region have been examined. 

The Coraco-Beachialis, Fig. 107 (i i), may next be dis- 
sected. It arises from the coracoid process, and extends 
obliquely downwards to the middle third of the humerus 
into the inner part of which it is inserted^ between the brachi- 
alis anticus and deltoid in front, and the triceps extensor 
behind. In dissecting this muscle, the student must be care- 
ful not to cut the external cutaneous nerve, which commonly 
passes obliquely through it from above downwards and out- 
wards. The coraco-brachialis elevates and draws the arm 
forwards, and in front of the thorax ; it can also rotate it 
outwards. When the arm and forearm are fixed, both this 
and the biceps can act on the scapula. 

The arteries which supply the biceps and coraco-brachialis 
muscles, are branches from the axillary and brachial ; they 
do not require any particular description. 

The nerves are derived principally from the external cuta- 
neous. Before raising the biceps and coraco-brachialis, it 
will be proper to proceed with the dissection of the brachial 
vessels and nerves. 

The brachial artery, vence comites, and median nerve, should 
be dissected down the arm together. The nerve will be found 
at first, lying in front and a little to the outside of the artery, 
near to the coraco-brachialis muscle, but gradually, as it de- 
scends, getting to the inside of it. The external cutaneous 
nerve sometimes comes from the median, instead of the bra- 
chial plexus, and, not unfrequently, a branch is given oft' from 
the median, which joins the external cutaneous beneath the 
biceps. The median nerve is sometimes found behind the 
brachial artery. 

The Brachial Artery, Fig. 92 (i o), is a continuation of 
the axillary. It extends from the lower borders of the ten- 
dons inserted into the bicipital groove to the bend of the 
arm, where it divides into the radial and ulnar. It is not 
covered by any muscle throughout its whole course, unless 
it is overlapped by the belly of the biceps, when that muscle 
is unusually developed. It is in relation on the outside 
with the coraco-brachialis above, and the biceps lower down. 
Behind, it is in relation above with the tendons of the teres 



DISSECTION OF THE ARM. 253 

major and latissimus dorsi, tlie triceps extensor, and the co- 
raco-bracHalis; below tliese it rests on the brachialis anticus. 
In the upper part of the arm it is placed on the inner side 
of the humerus, but is in front of the bone, where it rests 
on the brachialis anticus. 

At the bend of the arm it is situated beneath the aponeu- 
rotic expansion from the tendon of the biceps muscle, which 
protects it to some extent when the median basilic vein is 
opened in bleeding. To ascertain the exact position of it, 
before opening the vein the biceps should be relaxed, other- 
wise the tension of this aponeurosis might prevent the pulsa- 
tion of the artery being felt. The median nerve here lies on 
the inner side of the artery. 

Usually there is no necessity for opening a vein over 
either the artery or nerve, and hence the liability of wound- 
ing either of them may be avoided. The anomalies which 
occur in the brachial artery are interesting in a surgical 
point of view ; but they vary so much, that a description of 
them must be omitted. It may be mentioned, however, that 
the one most commonly met with is a high division of the 
artery into the radial and ulnar, which may occur at any 
point in the arm, even as high as the axilla. It gives off the 
four following branches :— 

The superior profunda^ Fig. 92 (15), arises just below the 
tendon of the teres major, and passes obliquely downwards 
and backwards to enter the fissure between the two heads of 
the triceps which arise from the humerus ; it accompanies 
the musculo-spiral nerve. Sometimes this branch arises in 
common with the posterior circumflex, or with the inferior 
profunda. 

The inferior profunda^ Fig. 92 (1 e), arises lower down, and 
proceeds obliquely downwards to the inner part of the elbow- 
joint, accompanying in the latter part of its course the ulnar 
nerve. 

The nutritious branch is given off near the middle of the 
humerus, which it penetrates through the nutritious foramen. 

The anastomotic branch, Fig. 92 (17), arises usually about 
two inches above the bifurcation into the radial and ulnar, 
and goes to the inner part of the elbow. These branches, 
except the nutritious, will be noticed again in connection 
with the vascular anastomosis around the elbow-joint. 
22 



254 THE UPPER EXTREMITY. 

The YENJa Comites consist of two veins, one on each side 
of the artery; they communicate frequently with each other 
across it. Sometimes there is found a collateral vein open- 
ing into the vense comites, both in the upper and lower part 
of the arm. These veins are to be cut away in dissecting the 
artery. 

The Ulnar Nerve, Fig. 93 (3), passes down, at first, close 
to the inner side of the artery, but gradually diverges from 
it as it proceeds towards the notch between the inner con- 
dyle and the olecranon process, through which it goes to the 
forearm. It gives ofi" no branches in the arm. It is ac- 
companied in the lower part of its course, as before men- 
tioned, by the inferior profunda artery. 

The Musculo-Spiral Nerve, Fig. 108 (15), cannot be 
traced at this stage of the dissection further than the fissure 
which it enters with the superior profunda artery in the tri- 
ceps extensor muscle. Before it enters the fissure it usually 
gives ofi' two or three small branches, which go to the muscles 
and the skin on the inner part of the arm. 

The belly of the biceps muscle may now be divided near 
the junction of its two heads, and turned upwards and down- 
wards, to expose the external cutaneous nerve and the bra- 
chialis anticus muscle. The nerve^ Fig. 108 (5), will be found 
passing obliquely downwards and outwards between the bi- 
ceps, and the brachialis anticus to become subcutaneous at 
the outer part of the bend of the arm. It supplies branches 
in its course to the coraco-brachialis, the biceps, and the bra- 
chialis anticus. Its cutaneous branches may now be traced 
for a short distance down on the forearm. 

The Brachialis Anticus, or Internus, Fig. 109 (1 e), arises 
from the whole of the anterior surface of the humerus, from 
the deltoid ridge to near the elbow-joint. It extends on both 
sides beyond the biceps, but more on the inner than on the 
outer side. It extends a little upwards in its origin on each 
side of the insertion of the deltoid. Its fibres converge to 
form a short tendon, which is inserted into the anterior and 
lower part of the coronoid process of the ulna. The tendon 
of the biceps lies partly upon it and to its outside. This 
muscle assists the biceps in flexing the forearm on the arm ; 
it also withdraws the synovial membrane from the angle of 



DISSECTION OF THE ARM. 



255 



tlie joint. In case of fracture of the coronoid process, it may- 
draw the fragment upwards. 

When the tendons of this muscle and the biceps are dis- 
sected, and reflected downwards, the anterior part of the 
elbow-joint is exposed, being cov- 
ered only bj a few ligamentous Fig. 109. 
fibres. On the outside of the 
brachialis anticus, and applied 
closely to it, is the supinator 
longus muscle. When these mus- 
cles are separated, the musculo- 
spiral nerve and the superior pro- 
funda artery will be found deeply 
embedded between them. 

The arm may now be turned 
over for the purpose of dissecting 
the back of it. The skin and su- 
perficial fascia may be removed 
by dissecting from either the in- 
ner or outer side. After examin- 
ing the brachial aponeurosis, it is 
to be removed by dissecting in 
the direction of the fibres of the 
triceps extensor muscle, having 
made that muscle tense by flex- 
ing the forearm on the arm and 
fixing the scapula. 

The Triceps Extensor, Fig. 
110 (lo, 14, 19), arises by three 
heads, one from the scapula, and 
two from the humerus. "TliQfirst^ 
or longest head, arises from the in- 
ferior costa of the scapula, occu- 

An Anterior View OF THE Deep-seated MrscLES op the Arm. ]. Clavicle. 

2. Coracoid process of the scapula. 3. Acromion scapula>. i. Head of the os 
humeri. 5. Tendon of the long head of the biceps. 6. Upper portion of the co- 
raco-brachialis. 7. Origin of the short head of the biceps. S. Body of the coraco- 
brachialis. 9. Insertion of the pectoralis major. 10. Latissimus "dorsi. 11. In- 
sertion of the deltoid. 12. Origin of tho brachialis internus. 13. Insertion of tho 
coraco-brachialis. 14. Middle portion of tho triceps. 15. Its lower anterior por- 
tion. If). IJody of the brachialis anticus. 17. Internal condyle. 18. 10. Inser- 
tion of tho brachialis anticus. 20. Supinator radii lono-ns. "21. Opening mndo 
in the capsular ligament. 22. Cut tendon of tho biceps^it its insertion. 23. Su- 
pinator radii brevis. 24. Aponeurosis. 




256 



THE UPPER EXTREMITY. 



Fig. 110. 



pying about an incli, commencing at tTie lo'^ver part of 
tlie glenoid ca^dty, "^liere it is slightly connected to tlie 
capsular ligament. Tlie second head arises from the pos- 
terior part of the humerns, commencing just below the great 

tuberosity, and extending 
down to the external condyle, 
from which it also arises in 
connection with the anconeus ; 
some of its fibres arise from 
the external intermuscular 
septum. The tliird and short- 
est head arises from the inner 
and back part of the humerus, 
'commencing just below and 
behind the insertion of the 
teres major, and extending 
down to the internal condyle ; 
some of its fibres come from 
the internal intermuscular 
septum. This head is some- 
times called the Irachialis ex- 
ternus. These three heads 
unite above the middle of the 
arm, and form a large muscu- 
lar belly, which ends in a 
broad flat tendon, which is in- 
serted into the olecranon pro- 
cess, and connected with the 
aponeurosis of the forearm. 
This muscle, it will be seen, 
occupies in its origin nearly 
the whole of the posterior sur- 
face of the humerus. It ex- 

A Lateral Tietv of the Deep-seated MrscLES ox the Back of the Arm:. 
— 1. Section of the clavicle. 2. Fossa supra-spinata of the scapula. 3. Base of 
the scapula. 4. Coraco-acromial ligament. 5. Coracoid process. 6. Origin of 
the coraco-brachialis. 7. Section of the subscapularis muscle. 8. Head of the os 
humeri. 9. Section of the body of the scapula. 10. Origin of the longhead of the 
triceps. 11. Insertion of the latissimus dorsi. 12. Edge of the biceps flexor 
cubiti. 13. Coraco-brachialis. 14-, 15. Origin of the second head of the triceps. 
16. Lower portion of the coraco-brachialis. 17. Body of the biceps. IS. Body of 
the triceps. 19. Origin of the third head of the triceps. 20,21. Its middle portion, 
known as the braehialis externus. 22. Brachialis anticus. 23. Its insertion. 24. 
Posterior ligament of the elbow. 25. 26. Origin of the flexors of the forearm. 27. 
Prolongation of the tendon of the biceps to the fascia brachialis. 28. Olecranon. 




DISSECTION OF THE FOEEARM. 257 

tends the forearm on tlie arm, and draws the synovial mem- 
brane from the joint when the forearm is extended. Bj its 
long head it can act on the scapula. "When the olecranon 
process is broken off, it may draw it upwards. 

The mnsculo-spiral nerve and superior profunda artery 
may now be traced in the spiral groove through the triceps 
muscle. To do this the muscle must be divided along the 
course of the artery and nerve, when the branches given off 
by them to the muscle, while passing through it, may be ob- 
served. 

The artery^ on reaching the outer and lower part of the 
arm, divides into several branches, which are distributed 
about the elbow-joint, some of them anastomosing with the 
anastomotic and recurrent branches of the radial and poste- 
rior interosseous arteries. 

The nerve^ when it leaves the triceps, gets between the 
brachialis anticus and supinator longus muscles, between 
which it goes to the bend of the arm, where it divides into 
the radial and posterior interosseous. These divisions will 
be traced in the dissection of the forearm. The internal and 
external cutaneous hranclies of this nerve have been noticed. 
Besides supplying muscular branches to the triceps extensor, 
it sends filaments to the brachialis anticus, supinator longus, 
and extensor carpi radialis longior. 

In dissecting the forearm, it will be sufS.cient to remove, in 
the first place, the skin in front down to the wrist. To do 
this, the incision which was made to dissect the arm may be 
continued down the middle of the forearm to the wrist, where 
a transverse incision is to be made. The vessels and nerves 
contained in the superficial fascia of the forearm, both in 
front and on the back, are the same as have been seen in the 
previous dissection. If they have been preserved, the stu- 
dent will have no dif&culty in tracing them. 

The veins vary so much in their arrangement on the fore- 
arm that it is hardly necessary to give any particular descrip- 
tion of them. If they have been injected, they are distinctly 
seen and easily followed. In the living person, especially if 
not fat, they are made prominent under the skin by com- 
pressing the veins of the arm. They anastomose freely with 
each other, forming a complete network. They are divided 
into the radial^ median^ and ulnar. If the student should 
wish to trace them and the cutaneous nerves, lie must dissect 

22"^' 



258 THE UPPER EXTEEMITY. 

the skin from the whole of the forearm and the back of the 
hand at the same time. If this be done, the parts must be 
kept covered with the integument or with wet cloths during 
the intervals between the times allotted to dissecting. 

The Internal Cutaneous T^erve, Fig. 103 (e, 7), will be 
found to continue down the forearm to the wrist; the anterior 
branch, which was seen in connection with the median basilic 
vein, on the front part, and the posterior branch on the back 
part of the arm. These branches are situated on the ulnar 
side. The anterior frequently anastomoses near the wrist with 
a branch from the ulnar. 

The External Cutaneous jSTerve, Fig. 104 (4), is situated 
on the radial side. Near the lower third of the forearm it 
divides into two branches; one continues down to the integu- 
ment, covering the ball of the thumb, and usually sends a 
filament through the deep fascia to ramify on the radial ar- 
tery ; it anastomoses with the radial nerve ; the other branch 
is reflected round to the back of the forearm, where, it also 
anastomoses with the radial. 

The lower external cutaneous branch of the musculo-spiral 
nerve will be found passing down on the back of the forearm 
to near the wrist. Branches of the radial and ulnar nerves are 
distributed on the back of the hand and fingers ; but these 
will be traced more readily from the main trunks. 

Beneath the superficial fascia is a thick, dense o.poneurosi^^ 
Fig. 106, which invests the muscles of the forearm generally, 
and furnishes fibrous sheaths for them separately. In struc- 
ture, it is similar to the brachial aponeurosis. It is thicker 
behind than in front, and in the upper than in the lower part 
of the arm. It gives origin to muscular fibres both from its 
under surface and from the processes which it sends in be- 
tween the muscles, especially near the elbow. Its connections 
with the brachial aponeurosis and with the fibrous expansions 
from the tendons of the biceps and triceps, have been seen. 

It is firmly attached to the olecranon process and to the 
inner part of the ulna down to the styloid process. Below, 
it is connected to the anterior and posterior annular liga- 
ments. Between its attachments to the upper part of the 
ulna there is a subcutaneous surface on that bone. Just 
below the bend of the arm it stretches across a sulcus that is 



DISSECTION OF THE FOREARM. 259 

formed by the anterior and posterior muscles of the forearm. 
There is a deficiency in it in front of the elbow-joint which 
allows the superficial fascia to join the deep areolar tissue, 
and also the vena communicans to reach the deep-seated 
veins, Fig. 106 (e). 

When this aponeurosis is removed from the front of the 
forearm as far as it can be done without interfering with the 
muscles which partly arise from it, a sulcus will be observed 
extending from the bend of the arm to the wrist, and separa- 
ting the muscles on the back from those on the front of the 
forearm. The upper part of this sulcus or depression is quite 
broad and deep. In it are found the median nerve and the 
bifurcation of the brachial artery, and the vense comites. The 
radial artery and its corresponding veins, occupy this sul- 
cus nearly its whole length ; the middle third contains also 
the radial nerve. On the inner side of the lower two-thirds 
of the forearm is another sulcus^ which contains the ulnar 
artery, its venas comites, and the ulnar nerve. 

There are eight muscles on the anterior part of the forearm. 
Two of these are inserted into the radius ; they are the pro- 
nators. Two of them pass over the wrist-joint to be inserted 
into two of the metacarpal bones ; these are carpal flexors. 
Three of them go to the thumb and fingers; these are digital 
flexors \ the one going to the thumb is called \hQ flexor longus 
pollicis. The eighth one, the palmaris longus^ is connected to 
the annular ligament and palmar aponeurosis. 

The student should familiarize himself with these muscles 
by making the several movements with his own hand as they 
respectively depend upon them. Three simple movements, 
such as flexing the fingers and thumb, then the hand on the 
forearm, and lastly, turning the hand on the palm, call into 
action seven of these muscles. A familiarity with their 
actions will assist liim greatly in recollecting their names and 
their relative position. In dissecting them, it is better to 
commence on the radial side. The two most prominent 
ones on this side are the pronator radii teres and flexor carpi 
radialis. They form the inner boundary of the sulcus in 
which lies the radial arter}^ 

The Pronator IIadii Teres, Fig. Ill (.1), arises from the 
internal condyle and aponeurosis of the ibrearm, and also by 



260 



THE UPPER EXTREMITY. 



Fig. 111. 



a small head, from tlie coronoid process of tlie ulna. The 
median nerve passes between these two origins. Its fibres 
pass obliquely downwards and outwards, to be inserted into 
the outer part of the middle third of the radius. The upper 
part of this muscle is superficial and prominent, while the 
lower part is deep-seated, having the radial artery and nerve 
in front of it. It rotates the radius inwards, and pronates 
the hand; it may also assist in flexing 
the forearm. 

The Flexor Carpi Eadialis, Fig. Ill 
(5), arises from the internal condyle and 
fascia, including the intermuscular sep- 
tum, in common with the preceding mus- 
cle. It forms a thick belly which becomes 
tendinous near the middle of the forearm, 
and continues so to its insertion into the 
base of the metacarpal bone of the index 
finger. The dissection of this muscle 
beneath and below the annular ligament 
with the lower part of the others which 
go to the hand, must be postponed until 
the palm of the hand is dissected. It 
flexes the hand on the forearm, and may 
assist in pronation and abduction of the 
same. 

The Palmaris Lokgus, Fig. Ill (e), 
is the next muscle to be dissected. Its 
origin is similar to that of the flexor 
carpi radialis. It forms a short belly, 
which ends in a long, slim tendon ; this 
extends down the forearm to the annular 
ligament and palmar aponeurosis, into 
which it is inserted. It is sometimes 

Superficial Layer of the Muscles of the Forearm:. — 1. The lower part 
of the biceps, with its tendon. 2. A part of the brachialis anticus, seen beneath 
the biceps. 3. A part of the triceps. 4. The pronator radii teres. 5. The flexor 
carpi radialis. 6. The palmaris longus. 7. One of the fasciculi of the flexor sub- 
limis digitorum: the rest of the muscle is seen beneath the tendons of the palmaris 
longus and flexor carpi radialis. 8. The flexor carpi ulnai-is. 9. The palmar_ 
fascia. 10. The palmaris brevis muscle. 11. The abductor pollicis muscle. 12. 
One portion of the flexor brevis pollicis; the leading line crosses a part of the 
abductor pollicis. 13. The supinator longus muscle. 14, The extensor ossis raeta- 
carpi, and extensor primi internodii pollicis, curving around the lower boi'der of 
the forearm. 




DISSECTION OF THE FOREARM. 261 

absent. It flexes the hand, and makes tense the pahnar apo- 
neurosis. It is separated from the muscle beneath it by a 
thick fascia. 

The Flexor Carpi Ulnaris, Tig. Ill (8),is placed on the 
nlnar side of the palmaris longus. It arises from the internal 
condyle, and from the ulna nearly its whole length, and 
from the fascia of the forearm. The ulnar nerve passes 
between its origins from the condyle and the olecranon pro- 
cess. Its origin from the lower part of the ulna is apo- 
neurotic. It is inserted into the pisiform bone, and through 
it into the metacarpal bone of the little finger ; it is, also, 
connected by some fibres with the muscles of the little finger. 
Its tendon is much shorter than that of the flexor carpi 
radialis. It flexes the hand, and assists in adduction. The 
ulnar artery and nerve are situated along the outer border of 
its inferior two-thirds. 

The flexor carpi radialis and palmaris longus may now be 
divided about three or fo\ir inches below their origin, and 
turned upwards, detaching the fibres from the intermuscular 
septa. The following muscle will then be exposed. 

The Flexor Sublimis or Perforatus Digitorum Com- 
munis, Fig. Ill (7), arises from the internal condyle, internal 
lateral ligament, and from both bones of the forearm; from 
the coronoid process of the ulna, and from the radius below 
its tubercle ; it also obtains some fibres from intermuscular 
septa. It forms a large muscular belly, which terminates in 
four tendons a little below the middle of the forearm ; these 
tendons pass under the annular ligament, the two on the 
radial side being situated somewhat anterior to the others, 
and through the palm of the hand, to be inserted into the 
second row of phalangeal bones. It flexes the fingers, and 
assists in flexing the hand and forearm. 

Before proceeding further with the dissection of the mus- 
cles, the arteries and nerves of this region should be examined. 
Some of them have already been seen, but not dissected and 
studied. , 

There are three arteries in the forearm which extend from 
the bend of the arm to the wrist. They are the radial, 
the ulnar, and the anterior interosseous. From those 
three arteries recurrent branches are given off, to anastomose 
around the elbow-joint, with the anastomotic and two pro- 
found branches of the brachial artery. 



262 



THE UPPER EXTREMITY. 



Fig. 112. 



The Radial Artery, Fig. 112 (i 2), although usnally not so 
arge as the ulnar, appears to be a continuation of the brachial. 

It is covered in front merely by the 
integument and aponeurosis; hence 
it is superficial in its whole course. 
It has one muscle in relation with 
it on the outside, the supinator Ion- 
gus ; two on the inner side, the pro- 
nator radii teres, and flexor carpi 
radialis ; and five behind it, and on 
which it lies. These are arranged 
in the following order, commencing 
above: the supinator brevis, pro- 
nator radii teres, flexor sublimis 
digitorum, flexor longus pollicis, 
and the pronator quadratus ; below 
this last muscle the artery rests on 
the radius. 

Near its commencement it gives 
off quite a large branch, the radial 
recurrent^ Fig. 112 (13). This is 
distributed to the muscles on the 
outside of the elbow, and anasto- 
moses with the superior profunda. 
In its course down the arm it gives 
off numerous branches, which are 
not named. In the lower part of 
the arm it sends off the sujperficial 
volar branchy Fig. 112 (14), which 
either passes over the mass of 
muscle that forms the thenar of the 

The Arteries of the Forearm. — 1. The lower part of the biceps muscle. 2. 
The inner condyle of the humerus, with the humeral origin of the pronator radii 
teres and flexor carpi radialis divided across. 3. The deep portion of" the pronator • 
radii teres. 4. The supinator longus muscle. 5. The flexor longus pollicis. 6. 
The pronator quadratus. 7. The flexor profundus digitorum. 8. The flexor carpi 
ulnaris. 9. The annular ligament, with the tendons passing beneath it into the 
palm of the hand; the figure is placed on the tendon of the palmaris longus mus- 
cle, divided close to its insertion. 10. The brachial artery. 11. The anastomotica 
inosculating superiorly with the inferior profunda, and inferiorly with the anterior 
ulnar recurrent. 12. The radial artery. 13. The radial recurrent artery inoscula- 
ting with the termination of the superior profunda. 14. The superficialis volae. 
15. The ulnar artery. 16. Its superficial palmar arch giving off digital branches to 
three fingers and a half. 17. The magna pollicis, and radial artery. 18. The 
posterior ulnar recurrent. 19. The anterior interosseous artery. 20. The posterior 
interosseous, as it is passing through the interosseous membrane. 




DISSECTION OF THE FOEEAEM. 263 

thumb to unite with the superficial palmar arch, or it may 
end in branches to these muscles. Sometimes this branch is 
very large, and forms a considerable portion of the palmar 
arch, or it may divide into digital branches. In this dissec- 
tion the radial artery disappears under the tendons of the 
extensor muscles of the thumb. 

Sometimes the radial artery leaves the anterior part of the 
forearm, some distance above the carpus, and winds round 
the radius to the back of the limb. In this case the pulse 
cannot be felt at the wrist, at least on the radial side. 

The radial artery is accompanied by venae co mites, one on 
each side of it. They require no particular description. 

The relation of the Eadial ISTerve, Fig. 108 (le), to the 
radial artery, is such that it is required to be dissected and 
studied at the same time. It is, as has been seen, the anterior 
division of the musculo-spiral. It lies close to the inner side 
of the supinator longus in the upper two-thirds of the fore- 
arm, and is in direct relation with the radial artery only in 
the middle third. In the upper third the nerve proceeds 
from the outer part of the elbow, while the artery descends 
from the centre of the bend of the arm. From these points 
they converge so as to meet at the junction of the upper 
with the middle third. They separate again at the junction 
of the middle and lower thirds; the nerve passing beneath 
the supinator longus, and over the radius to reach the back 
part of the arm and hand. It is superficial in this part of 
its course. The nerve can generally be felt beneath the skin, 
during life, where it winds over the radius. 

The radial nerve on the dorsum of the hand. Fig. 114 (4), 
divides into an external and an internal branch. The external 
branch supplies the integument on the outer and back part 
of the thumb, and anastomoses with the external cutaneous 
nerve. The internal branch passes obliquely over the exten- 
sor tendons of the thumb, and is distributed to the integument 
of the index and middle fingers, and sometimes to the radial 
side of the ring finger, and tlie ulnar side of the thumb. It 
anastomoses with the dorsal branch of the ulnar. 

The Ulnae Aetery, Fig. 112 (ir,), is situated on the 
inner side of the arm. Its upper third has an oblique direc- 
tion from above downwards, and fi"om without inwards, and 
is placed beneath the pronator radii teres, ilcxor carpi radi- 



264 THE UPPER EXTREMITY. 

alis, palmaris longus, and flexor sublimis digitorum. Tlie 
deptli and direction of it in this part of its course should be 
observed. In the lower two-thirds of the forearm it is super- 
ficial, and situated on the radial side of the flexor carpi ulna- 
ris, which may serve as a guide for finding it. The flexor 
sublimis lies on the outer side, and the flexor profundus be- 
hind it. The median nerve is separated from the artery at 
first by the coronoid head of the pronator radii teres, and 
below this it is situated to the outer side of it. 

It gives off a recurrent branch, Fig. 112 (ii, is), which 
usually divides into an anterior and posterior. The oMerior 
is small, and is distributed in front of the joint; \ki.Q 'posterior 
is larger, and passes up beneath the flexor sublimis, to the 
notch between the olecranon process and internal condyle, 
where it meets with the ulnar nerve. It anastomoses with 
the inferior profunda and anastomotic branches of the bra- 
chial artery, and also sends small branches to the interior of 
the joint. 

Just below the origin of the recurrent, it gives off the 
IxTEEOSSEOus Arteey, Fig. 112 (19). This soon divides 
into the anterior and posterior interosseous; the /ormer passes 
down the forearm resting on the interosseous ligament, while 
the latter perforates the ligament, and is distributed to the 
muscles on the back of the limb. These will be examined 
at another time. There are no other branches given off from 
the ulnar, which are named, until it reaches the carpus, where 
it sends off a small metacarpal hrancli^ which goes to the 
dorsum of the little finger, and carpal hranches^ which anas- 
tomose on the carpus, both in front and behind, with corre- 
sponding branches of the radial artery. The ulnar artery 
leaves the forearm by passing over the annular ligament close 
to the radial side of the pisiform bone, where it is covered by 
a few ligamentous fibres. 

The ulnar, as was stated in connection with the bifurcation 
of the brachial artery, may commence at any point on the arm. 
An important anomaly is occasionally met with in its position; 
instead of passing beneath the muscles it may pass over them, 
or all of them except the palmaris longus. In this case it 
may be even superficial to the aponeurosis of the forearm. 
It also varies greatly in size ; the interosseous or radial, or 
both of them, being at the same time larger or smaller than 



DISSECTION OF THE FOREARM. 



265 



Fig. 113. 



common. It is important to understand tlie position of this 
artery in bleeding at the bend of the arm. 

The ulnar artery is accompanied by its vense comites. 

The Ulnar Nerve, Fig. 118(3), enters the forearm through 
the notch between the internal con- 
dyle and olecranon process, and be- 
tween two heads of the flexor carpi 
ulnaris. It then passes obliquely 
beneath the inner head, to join the 
ulnar artery at the junction of the 
upper with the middle third of the 
forearm. It accompanies the artery 
in the rest of its course, being situ- 
ated on the ulnar side. It sends 
articular filaments to the joint as it 
passes oyer it ; muscular branches to 
the flexor carpi ulnaris, and flexor 
profundus digitorum ; and cutaneous 
branches, one to the front of the 
lower part of the forearm and hand, 
and another to the dorsum of the 
same parts. The latter branch leaves 
it about two inches above the carpus, 
and passing beneath the flexor carpi 
ulnaris. Fig. 118 (e), gets round to 
the back of the wrist and hand, where 
it divides into several branches, 
which are distributed to the little 
and ring fingers. It also anasto- 
moses with the radial. 

The Median Kerve, Fig. 113 (1), 
after passing between the two heads 
of the pronator radii teres, goes 
down the middle of the forearm 
between the flexor sublimis in front, 
and the flexor profundus behind, 
to within about two inches of the 
wrist, where it gets on the outer side 
of the tendons of the flexor sublimis, 
and becomes superficial. It passes 
beneath the annular ligament to on- 




A View of the Nerves on 

the front of the sfouearm. 

1. Tho nuHiian nerve. 2, Aute- 
rior branch of tho nuisoulo-spiral 
or radial nerve, o, Tho ulnar 
nerve, 4. Division of the median 
nerve in the palm to the thumb, 
first, second, and r:<dial side of 
the third finger, o. Division of 
tho ulnar nerve to tho ulnar 
side of the third, and both sideg, 
of the fourth fiuj^ier. 



23 



266 



THE UPPER EXTREMITY. 



ter the palm of the hand. It supplies branches to all the 
muscles on the front part of the forearm except the flexor 
carpi nlnaris. The anterior interosseous is the largest branch. 
The course of this is the same as that of the anterior inter- 
osseous artery, with which it will be noticed. 

Three muscles remain to be dissected on the front of the 
forearm ; these are the flexor profundus digitorum, flexor 
longus poUicis, and the pronator quadratus. The first two 
lie parallel to each other, and occupy 
Fig. 114. the same plane ; there is no very 

distinct line of demarcation or areo- 
lar interspace between them. The 
areolar tissue may be removed from the 
anterior surface of both of them at the 
same time. 

The Flexor Profundus, or, Per- 
FORANs Digitorum, Fig. 114 (4), arises 
from the upper two thirds of the ulna 
and the interosseous ligament contigu- 
ous to it, and sometimes by a small 
slip from the radius. It is a large 
muscle, occupying the inner two thirds 
of the anterior interosseous space ; near 
the carpus it divides into four ten- 
dons, which pass beneath the .annular 
ligament to go to the last row of pha- 
langeal bones into which they are in- 
serted. It flexes the last phalanges, and 
otherwise assists the flexor sublimis in 
flexing the fingers and hand. 

The Flexor LojS"gus Pollicis, Fig. 
114 (5), arises from the radius, com- 
mencing just below the tubercle, and 
extending to within about two inches 
of its lower end ; also from the inter- 
osseous ligament, and frequently by a 

The Deep Layer of Muscles of the Foreaesi. — 1. The internal lateral li- 
gament of the elbow-joint. 2. The anterior ligament. 3. The orbicular ligament 
of the head of the radius. 4. The flexor profundus digitorum muscle. 5. The flexor 
longus pollicis. 6. The pronator quadratus. 7. The adductor pollicis muscle. 8. 
The dorsal interosseous muscle of the middle finger, and palmar interosseous of the 
ring finger. 9. The dorsal interosseous muscle of the ring finger, and palmar in- 
terosseous of the little finger. 




DISSECTION OF THE FOKEAEM. 



267 



Fig. 115. 



round fasciculus from the coronoid process of the ulna. It 
ends in a tendon which passes beneath the annular ligament, 
and continues to the last phalangeal bone of the thumb, 
into which it is inserted. It flexes the last phalanx of the 
thumb. 

The Peonator Quadratus, Fig. 114 (e), and 115 (9), is a 
short, square muscle, placed beneath the preceding muscles. 
It arises from the inner part of the 
lower fifth of the ulna ; its fibres pass 
transversely, or nearly so, across the 
interosseous space, and are inserted into 
the lower part of the radius, near its 
outer border.. It rotates the radius in- 
wards, and thus pronates the hand. 

The Anterior Interosseous Ar- 
tery, Fig. 112 (1 9), may now be exam- 
ined, and also its accompanying nerve. 
They usually rest on the interosseous 
ligament near the median line. The 
artery passes through the ligament near 
the pronator quadratus to the dorsum 
of the carpus, where it divides into 
several small branches. Occasionally 
it gives off quite a large branch, which 
accompanies the median nerve down 
the forearm. 

The Anterior Interosseous Nerve, a View op the prona- 
Fig. 108 (1 3), terminates in a filament tors op the Forearm.— i. 
to the pronator quadratus and one to Sl'^TcaptiaHig^^eoi 




the carpal articulations. Both the ar- 
tery and nerve give off branches to the 
muscles which lie contiguous to them 
in the interosseous space. 



of the elbow. 5. Interosse- 
ous ligament. 6. Origin of 
the pronator radii teres. 
7. Its insertion. 8. Supi- 
nator radii brevis. 9. Pro- 
nator quadratus. 10. Ten- 

The back of the forearm may now •^^^ °^ }^]^ \^\cq^s. ii. Car- 
be examined, and, at the same time, ^* 
the back of the hand. It is not necessary to refer again 
to the fascia or the subcutaneous vessels and nerves of 
this region, as they were described in connection with the 
anterior ^ part of the forearm. The remarks which were 
made with reference to the study of the muscles on the 



268 THE UPPER EXTREMITY. 

forepart of the forearm will apply equally to tliose on the 
back part. Most of them are antagonist mnscles to those 
already learned. There are eleven, including the anconeus, 
and allowing no distinct muscle for the little finger. In 
arranging them according to their action, and comparing 
them with the flexors and pronators, the student will find 
two supinators opposed to the two pronators ; three carpal 
extensors to the two carpal flexors ; three extensors of the 
thumb, one for each joint, to the single long flexor ; one 
common extensor of the fingers to the two common flexors. 
The extensor of the index finger and the anconeus have no 
corresponding muscles in front. 

Six of these muscles are situated superficially, and may 
be dissected in the following order : — 

The Anconeus, Fig. 116 (i i), and Fig. 117 (4), is a small 
triangular-shaped muscle, situated on the posterior part of 
the elbow-joint. It arises from the external condyle of the 
humerus, immediately below the origin of the lower fibres 
of the triceps extensor, and from the external lateral liga- 
ment; it passes obliquely downwards and somewhat inwards, 
and is inserted into a triangular space on the upper and pos- 
terior part of the ulna. It assists the triceps in extending 
the arm, and might be considered an appendage to that 
muscle. It partly covers the elbow-joint posteriorly. 

The Supinator Longus, Fig. 116 (4), arises from the ridge 
which extends upwards from the external condyle, and from 
the external intermuscular septum of the brachial aponeurosis ; 
its origin commences just below the insertion of the deltoid 
and ends about an inch and a half above the condyle. Its 
fibres terminate in a tendon about the middle of the forearm, 
which goes down to be inserted into the lower end of the 
radius at the base of the styloid process. It rotates the radius 
backwards so as to supinate the hand. 

The Extensor Carpi Eadialis Longior, Fig. 116 (5), 
arises from the external condyloid ridge, immediately below 
the preceding muscle, and becomes tendinous near the junc- 
tion of the upper with the middle third of the forearm. 

The Extensor Carpi Eadialis Brevior, Fig. 116 (e), 
arises from the external condyle, and from the aponeurosis 
which partly surrounds it. It becomes tendinous a little 



DISSECTION OF THE FOEEAEM. 



269 



lower down than the preceding muscle. The tendons of these 
two carpal extensors are partly covered bj the supinator 
longus, and are so closely connected to each other that they 
appear to form a single tendon until they get near the wrist, 
where they separate, and, passing beneath the tendons of two 
of the extensor muscles of the thumb, 
and then through the same canal in the Fig. 116. 

posterior annular ligament, are inserted^ 
the longior into the base of the meta- 
carpal bone of the index finger, and 
the brevior into the metacarpal bone 
of the second finger. They extend the 
hand on the forearm, and also abduct 
it. The groove which their tendons 
occupy in passing over the radius is 
lined by a bursa. 

The ExTENsoE Digitoeum Commu- 
nis, Fig. 116 (s), is placed on the ulnar 
side of the muscles just described. It 
arises from the external condyle, from 
the aponeurosis around it, and from the 
ulna. About the middle of the fore- 
arm it divides into four small muscles, 
each of which ends in a tendon. The 
four tendons passing through a groove 
on the radius, and a canal beneath 
the annular ligament, expand on the 
back of the hand, being connected to- 
gether more or less by tendinous 
fibres, and finally are inserted into all 
the phalanges. On the dorsum of the 
fingers they are connected with the 
tendons of the interossei and lumbri- 

The Superficial Layer of MusciiES op the posterior aspect of the Fore- 
ARSr. — 1. The lower part of tho biceps. 2. Part of the brachialis antieus. 3. The 
lower part of tho triceps, inserted into the olecranon, 4. Tho supinator longus. 
5. The extensor carpi radialis longior. 0. Tho extensor carpi radialis brevior. 7. 
The tendons of insertion of these two muscles. 8. The extensor communis digito- 
rum. 9. Tho extensor minimi digiti. 10. Tho extensor carpi ulnaris. 11. Tho 
anconeus. 12. Part of tho flexor carpi ulnaris. 18. The extensor ossis metacarpi 
and extensor primi internodii muscles lying together. 14. The extensor secundi in- 
ternodii; its tendon is seen crossing tho two tendons of the extensor carpi radialis 
longior and brevior. 15. Tho posterior annular lignment. The tendons of the com- 
mon extensor are seen upon tho back of the hand, and their modo of distribution 
on tho dorsum of the lingers. 

23-^ 




270 



THE UPPER EXTREMITY. 



Fig. 117. 



cales. It extends all tlie fingers. The extensor minimi 
digit% Fig. 116 (9), may be considered a part of this mnscle, 
having the same origin, course, and insertion. Its tendon 
may pass through a separate canal beneath the annular liga- 
ment. 

The Extensor Carpi Ulnaris, Fig. 116 (10), arises from 
the external condyle, from the aponeurosis around it, and 
from the ulna below the insertion of the anconeus. It 
becomes entirely tendinous near the 
carpus, passes through a groove be- 
hind the styloid process of the ulna 
and a separate canal beneath the an- 
nular ligament, and is inserted into the 
base of the metacarpal bone of the 
little finger. It extends the hand, and 
adducts it. As an extensor, it acts in 
conjunction with the radio-carpal ex- 
tensors; as an adductor of the hand 
it co-operates with the flexor carpi 
ulnaris, although, as an extensor, it 
opposes this muscle. 

The student will meet with some 
difiiculty in separating the extensor 
muscles in the upper part of the fore- 
arm, on account of their arising from 
the same aponeurosis and intermuscu- 
lar septa. When they are separated 
from each other the dissection will 
necessarily appear rough and uneven. 
The remaining five muscles on the 
back of the forearm are deep-seated, 
and, except the anconeus, small, com- 
pared with those which have been dis- 
sected. The arteries are the posterior 
interosseous and the radial, together 
with some small branches on the dor- 

The Deep Layer of Muscles on the Posterior Aspect op the Forearm. — 
1. The lower part of the humerus. 2. The olecranon. 3. The ulna. 4. The 
anconeus muscle. 5. The supinator brevis muscle. 6. The extensor ossis meta- 
carpi pollicis. 7. The extensor primi internodii polllcis. 8. The extensor secundi 
internodii pollicis. 9. The extensor indicis. 10. The first dorsal interosseous 
muscle. The other three dorsal interossei are seen between the metacarpal bones 
of their respective fingers. 




DISSECTION OF THE FOKEARM. 



271 



sum of the hand. The nerves are the posterior interosseous, 
and the cutaneous branches of the radial and ulnar on the 
lower part of the limb, which, last were examined directly 
after the removal of the skin. 

The Supinator Brevis, Fig. 117 (5), is a short flat muscle, 
which arises from the external condyle, the ulna for a short 
distance below the lesser sigmoid cavity, and the external late- 
ral and orbicular ligaments. The fibres pass obliquely down- 
wards and outwards, and are inserted into the radius between 
its cervix and the insertion of the pro- 
nator radii teres. To expose it, the Fig. 118. 
supinator longus and the radio-carpal 
extensors must be divided a few 
inches below the elbow, and reflected 
upwards ; the anconeus should also be 
dissected up. 

The Posterior Interosseous Ar- 
tery will be seen just below the supina- 
tor brevis. It descends to the wrist, 
lying on the extensor muscles of the 
thumb and index finger. It gives off, in 
the upper part of its course, the poste- 
rior recurrent branch, which ascends be- 
neath the anconeus to anastomose with 
the superior profunda, and to send twigs 
to the elbow-joint. It supplies the mus- 
cles on the back of the forearm, and 
anastomoses on the dorsum of the wrist 
with branches from the radial, ulnar, 
and anterior interosseous arteries. 

The Posterior Interosseous 
Nerve, Fig. 118 (2), will be found 
passing through the supinator brevis, 
and then descending with the artery 
to near the middle of the forearm, 
where it dips down to the interosseous 
ligament, on which it continues to the 

A View op the Nerves on the Back of the Forearm axp IIaxp. — 1, 1. Tlio 
ulnar nerve. 2, 2, Posterior interosseous nervo. 3. Humeral cutanooui? branch. 
4. Dorsal branch of the radial nervo. 6, 5. A back view of the digital nerves. 6. 
Dorsal branch of tho ulnar nervo. 




272 THE UPPER EXTREMITY. 

wrist. It terminates in filaments to the carpal articula- 
tions. 

In its conrse it sends filaments to all the muscles on the 
back of the limb, except the supinator longus, extensor carpi 
radialis longior, and anconeus. 

The Extensor Ossis Metacarpi Pollicis, Fig. 117 (e), 
is the first deep muscle below the supinator brevis. It arises 
from the posterior and upper part of the radius and ulna, and 
from the intermediate portion of the interosseous ligament. 
Its tendon descends obliquely outwards over the lower part 
of the radius, and the carpus to be inserted into the base of 
the metacarpal bone of the thumb. It very frequently divides 
into two tendons, one of which goes to the trapezium. 

The Extensor Primi Internodii Pollicis, Fig. 117 (7), 
is the next small muscle. It arises from the radius and inter- 
osseous ligament, immediately below the preceding muscle, 
with which its tendon is closely connected. It is inserted into 
the base of the first phalangeal bone of the thumb. The line of 
separation between these two muscles is often very indistinct, 
except near their insertion. Their tendons pass through the 
same canal in the posterior annular ligament. 

The Extensor Secundi Internodii Pollicis, Fig. 117(8), 
arises from the middle third of the ulna and the interosseous 
ligament contiguous to it. Its tendon passes down over the 
lower end of the radius, about half an inch to the ulnar side 
of the tendons of the other two extensors of the thumb, 
and continues to the last phalanx, into which it is inserted. 
The last three muscles extend the three joints of the thumb; 
the first two also act as abductors of it. The student should 
observe the situation of the tendons of these muscles in his 
own wrist. They are seen very distinctly through the skin 
when the thumb is forcibly extended. They have an im- 
portant relation to the radial artery, which passes beneath 
them, and which will shortly be noticed. 

The Extensor Indicis, or Indicator, Fig. 117 (9), is the 
only muscle left. It arises from the ulna and interosseous 
ligament just below the muscle last described, and forms a 
small tendon which passes through the annular ligament with 
the common extensor of the fingers ; it joins and is inserted in 
common with, the tendon of that muscle which is appropriated 
to the index finger. Its use is to extend that finger by itself. 



THE PALM OF THE HAND. 273 

The Eadial Aetery may now be examined in its course 
over the wrist. It winds round the external lateral ligament 
of the wrist-joint, below the radius, and enters a triangular 
space between the tendons of the extensor muscles of the 
thumb ; leaving this space, where it is covered merely by the 
skin and fascia, it gets between the metacarpal bones of the 
thumb and index finger, and then disappears between the 
two heads of the first dorsal interosseous muscle, and enters 
the palm of the hand. It gives off the dorso-carj)al branch, 
which passes transversely beneath the tendons, on the back 
of the wrist, to anastomose with the dorso-carpal branch of 
the ulnar. From the arch thus formed, branches pass up 
to anastomose with the interosseous arteries; others descend 
in the interosseous spaces to the fingers. The branch, in the 
second interosseous space, is sometimes quite large. Other 
small branches are given off from it to the back of the thumb 
and forefinger. 

The canals in the posterior annular ligament may now 
be examined. There are six of them altogether. They are 
lined by synovial membrane so as to allow the tendons to 
glide through them with perfect facility, while each is kept 
in its proper place. The synovial membrane usually extends 
some distance above and below the ligament. Between the 
different openings the ligament is firmly attached to the bone 
beneath. The examination of the dorsal interosseous muscles 
may be postponed until the palm of the hand has been dis- 
sected. 

The Palm of the Hand. 

To dissect the front part of the hand it should be placed 
with the palm upwards ; the thumb and fingers should also 
be extended and fixed with hooks. It is immaterial in what 
direction the incisions are made for the purpose of removing 
the skin. In dissecting it from the inner part of the palm, 
it is to be recollected that the following muscle is inserted 
into the integument : — 

The Palmaris Brevis arises from the annular ligament 
and palmar aponeurosis, and passes, in fasciculi, transVersely 
inwards, and is inserted into the skin in front of the meta- 
carpal bone of the little finger near the inner border of the 



274 THE UPPER EXTREMITY. 

hand. Its action is to increase tlie depth of tlie liollow of the 
palm of the hand. 

Two cutaneous nerves^ one from the ulnar, and the other 
from the median, are distributed to the skin in the palm. 
These branches were noticed in the dissection of the median 
and ulnar nerves in the lower part of the forearm, as passing 
over the annular ligament to the hand. 

Between the skin and the palmar fascia there is usually- 
considerable fat, which must be dissected from the latter. 
The fascia is of a triangular shape, narrow above and broad 
below. It is attached to the annular ligament above; be- 
low it divides into four processes, one for each finger, and 
each of these again is subdivided into two others, which dip 
down to be inserted into the sheaths of the tendons of the 
flexor muscles of the fingers, and the ligaments of the joints 
beneath. The first mentioned processes are connected by 
transverse fibres, which form arches over the lumbricales 
and the digital arteries and nerves. The fascia is bound 
down by fibres which pass between the tendons to be 
attached to the metacarpal bones. It is very thin over the 
muscles of the thumb and little finger. This fascia should 
be noticed with reference to the formation of pus beneath it, 
and punctured woands in the palm of the hand. 

The Superficial Palmar Arch, Fig. 112 (le), and its 
tranches^ are situated immediately beneath the palmar fascia. 
These, with the branches of the median and ulnar nerves, should 
be dissected next. The arch is readily exposed by following 
the ulnar artery, or the superficialis volae, over the annu- 
lar ligament. It is situated nearly in the centre of the 
palm, with its convexity looking towards the fingers. The 
principal branches from the arch are the four metacarjMl 
Three of these correspond respectively with the second, third, 
and fourth interosseous spaces, while the fourth one passes 
down to the ulnar side of the little finger. 

Each of these arteries, except the one which goes to the 
ulnar side of the little finger, divides at the lower end of the 
space which it occupies, into tivo digital branches ; these extend 
along the contiguous sides of the fingers to their extremities. 

Those of the same finger anastomose freely with each 
other, especially in its pulpy portion. It usually requires 
some patience to dissect out these arteries in consequence of 



THE PALM OF THE HAND. 275 

the close adherence of cellulo-adipose substance to them. 
The superficial palmar arch is connected at its outer extre- 
mity with the superficialis volse, and another branch which 
proceeds from the radial artery to the index finger. Besides 
the branches already mentioned, there are several smaller 
ones derived from this arch, bat they require no special 
notice. 

Although the radial artery cannot be traced at the present 
time into the deep palmar arch, its digital branches to the 
thumb and forefinger may now be exposed. They occupy a 
position on the thumb and radial side of the forefinger, simi^ 
lar to that of the other digital branches on the fingers. It 
will be observed that the index finger is supplied equally by 
the radial and ulnar arteries. 

The Ulnae ISTerve, Fig. 113 (5), will be found entering 
the palm along with the ulnar artery, but instead of forming 
an arch, it divides into a deep and superficial branch. The deep 
one passes deeply into the palm of the hand, and across it be- 
neath the common flexor tendons to the muscles of the thumb. 
It perforates the short flexor of the little finger, and in its 
course supplies branches to the muscles of the little finger, the 
third and fourth lumbricales, and the corresponding inter- 
osseous muscles, terminating in the abductor indicis, adductor 
pollicis, and the inner head of the flexor brevis pollicis. The 
superficial one sends a branch to the inner side of the little 
finger, the short flexor of which it perforates. It then divides 
into two branches to supply the contiguous sides of the little 
and ring fingers ; it also sends a small branch to join the 
median nerve. 

The Median Nerve, Fig. 113 (4), enters the palm of the 
hand resting on the tendons of the long digital flexors. 
Having sent a branch to those muscles of the thumb which 
are not supplied by the deep branch of the ulnar, it divides 
into two parts, from which proceed five branches, to be dis- 
tributed as follows : — ■ 

One branch goes to each side of the thumb ; one to the 
radial side of the index finger ; the other two subdivide each 
into two branches, to supply the opposing sides of the index, 
middle, and ring fingers. They are expended mainly in the 
skin, which, at the extremities of the fingers, is su[)plied by 
them on the dorsal as well as on the palmar aspect. The digital 



276 THE UPPER EXTEEMITY. 

arteries and nerves may be dissected at tlie same time. The 
nerves will be found to be more superficial than the arteries. 

The tendons of the long flexors of the thumb and fingers, 
and the lumbricales, may now be examined. 

Beneath the annular ligament the tendons are surrounded 
by the carpal bursse, of which there are two ; one for the 
tendons of the fingers, and one for the tendon of the thumb. 
The former projects between the different tendons, extends 
some distance above the annular ligament, especially behind, 
and is prolonged downwards in the form of four pouches, one 
for the two tendons of each finger. The bursa on the flexor 
tendon of the thumb extends much further, both above 
and below the annular ligament. A proper examination of 
this bursa requires a division of the annular ligament. This 
may be done now, or postponed until the muscles of the 
thumb and little finger have been dissected. 

The tendons of the digital flexors, Fig. 119, pass down 
in front of the phalanges ; those of the sublimis to the 
second, and those of the profundus to the last row. They 
are kept in place by sheaths, composed of a dense fibrous 
structure, which is firmly attached to the margins of the 
groove on the palmar aspect of each of the phalanges of the 
first and second rows. In front of the articulations these 
sheaths are deficient or entirely absent. Each of these 
fibrous canals is lined by a synovial membrane, which is re- 
flected aroimd the tendons. 

The tendons of the flexor sublimis split, Fig. 119 (s), nearly 
opposite to the middle of each phalanx of the first row, and 
then reunite to be inserted into those of the second. The 
tendons of the flexor profundus pass through the openings 
thus formed ; above the slits they lie behind the tendons of 
the sublimis, but get in front below them ; they are inserted 
into the last row of phalanges. 

The tendon of the flexor longus poUicis passes over the 
trapezium, and between the two heads of the flexor brevis 
pollicis, and through a fibrous sheath to be inserted into the 
last phalangeal bone of the thumb. 

The Lumbricales, Fig. 119 (7, 7), are four small muscles 
which arise from the external sides of the tendons of the 
flexor profundus. Their tendons pass downwards and back- 
wards over the radial side of the metacarpo-phalangeal 



THE PALM OF THE HAND. 



277 



articulations, and are expanded on the back of the first row 
of phalanges, in connection with the tendons of the common 
extensor of the fingers. Their action cannot well be defined; 
it will depend on the action of other muscles, whether they 
assist in flexing or extending, in abducting or adducting the 
fingers. 

The four short muscles of the thumb may now be dissected. 
They form the palmar or thenar eminence, and are named 
according to their action on the thumb. 

The Abductor PoLLicis,Fig.ll9(2, 2), is the most super- 
ficial and external. It arises from the annular ligament and 
trapezium, and is inserted into the base of the first phalanx. 
It abducts the thumb. 

The Flexor Ossis Metacarpi, or, Opponens Pollicis, 
Fig. 119 (3), is partly overlapped by the preceding muscle, 
which, consequently, should be raised before the opponens 

Fig. 119. 

The Muscles of the Hand. — 1. 
The annular ligament. 2, 2. The ori- 
gin and insertion of the abductor pol- 
licis muscle ; the middle portion has 
been removed. 3. The flexor ossis 
metacarpi, or opponens pollicis. 4. 
One portion of the flexor brevis polli- 
cis. 6. The deep portion of the flexor 
brevis pollicis. 6. The adductor pol- 
licis. 7, 7. The lumbricales muscles, 
arising from the deep flexor tendons, 
upon which the numbers are placed. 
The tendons of the flexor sublimis have 
been removed from the palm of the 
hand. 8. One of the tendons of the 
deep flexor, passing between the two 
terminal slips of the tendon of the flexor 
sublimis, to reach the last phalanx. 9. 
The tendon of the flexor longus pol- 
licis, passing between the two portions 
of the flexor brevis to the last phalanx. 
]0, The abductor minimi digiti. 11. 
The flexor brevis minimi digiti. The 
edge of the flexor ossis metacarpi, or 
adductor minimi digiti, is seen project- 
ing beyond the inner border of the 

flexor brevis. 12. The prominence of the pisiform bone, 13. The first dorsal in- 
terosseous muscle. 




is dissected. It arises from the annular ligament and os 
scaphoides, and is inserted into the metacarpal bone of the 
24 



278 THE UPPER EXTREMITY. 

thumb. It opposes the thumb to the fingers, as in grasping 
anything in the palm. 

The Flexor Brevis Pollicis, Fig. 119 (4, 5), is the 
largest of the four short muscles of the thumb. It consists 
of two parts, separated by the tendon of the flexor longus 
pollicis. The anterior part is not unfrequently inseparably 
connected with the opponens, and the posterior with the 
adductor pollicis. The first arises from the annular ligament, 
trapezium, and scaphoides ; the second from the trapezoides, 
magnum, and base of the third metacarpal bone. The two 
parts unite and are inserted by two short tendons into the first 
phalanx. A sesamoid bone is commonly found in each of 
these tendons. As its name implies, it flexes the thumb. 

The Adductor Pollicis, Fig. 119(6), arises from the meta- 
carpal bone of the middle finger, nearly its whole length, 
and is inserted^ with the posterior part of the flexor brevis, 
into the first phalanx. It approximates the thumb to the 
forefinger. 

There are three short muscles in the palm which belong 
to the little finger. They form the hypothenar eminence. 

The Abductor Mixim Digiti, Fig. 119 (10), arises from 
the annular ligament and pisiform bone, and is inserted into 
the base of the first phalanx. It is the most superficial and 
internal of the short muscles of the little finger. It separates 
the little from the ring finger. 

The Flexor Brevis Miximi Digiti, Fig. 119 (n), arises 
from the annular ligament and unciform bone, and is inserted 
into the first phalanx. It is closely connected to the abductor. 
It flexes the little finger. 

The Adductor Minimi Digiti, Fig. 119 (n), arises from 
the OS unciforme and annular ligament, and is inserted into the 
metacarpal bone of the little finger. It may be compared 
to the opponens pollicis. It lies behind the flexor brevis. It 
draws the little to the ring finger. 

The annular ligament may now be examined and divided, 
and the tendons of the long flexors with the lumbricales re- 
moved from the palm, so as to expose the deep palmar arch 
and the interosseous muscles. 

The Annular Ligament, Fig. 119 (i), is attached on the 
inner side to the pisiform bone, and the tendon of the flexor 



THE PALM OF THE HAND. 279 

carpi ulnaris, and also to tlie unciform bone ; the nlnar nerve 
passes between these attachments. Externally it is connected 
to the scaphoides and trapezium. Its fibres are, for the most 
part, transverse. Its connection with the aponeuroses of the 
forearm and palm, and with the palmaris longus, and the 
short muscles of the thumb and little finger have already 
been seen. It subtends the deep sulcus in the anterior part 
of the carpus, and serves to keep the flexor tendons which 
pass beneath it in their proper place ; it also strengthens the 
carpus. 

The Kadial Arteky reaches the palm of the hand by pass- 
ing between the heads of the abductor indicis. Before termi- 
nating in the deep palmar arch, it gives off a digital branch 
to the index finger, and the arteria magna pollicis^ Fig. 118 
(i 7), which divides into two branches for the thumb. The 
former will be found passing behind the flexor brevis pollicis 
and adductor pollicis, and over the abductor indicis ; the 
latter passes between the abductor indicis and short flexor of 
the thumb. Their distribution was seen in the dissection of 
the branches of the superficial arch. 

The Deep Palmar Arch rests on the metacarpal bones 
and interosseous muscles, to which, and the carpus, it sends 
small branches. Three metacarpal branches are sent down- 
wards from it along the interosseous spaces to anastomose 
with the digital branches of the superficial arch. It ends 
on the ulnar side by joining a deep branch from the ulnar 
artery. 

The deep hranch of the ulnar nerve may be traced at the 
same time with the deep palmar arch. 

There are seven interosseous muscles — three palmar, 
and four dorsal. They occupy the spaces between the meta- 
carpal bones, being separated from each other by a thin apo- 
neurosis. The three palmar are called adductors, because 
they approximate the forefinger and the little and ring 
fingers to the middle finger, which is made to represent the 
median line of the hand. 

The adductor of the forefinger^ Fig. 120 (1), arises from the 
ulnar side of the upper and front part of the second meta- 
carpal bone, and is inserted into the first phalanx of the fore- 
finger. 

The adductor of the ring finger^ Fig. 120 (2), arises iTom the 



280 



THE UPPER EXTREMITY. 



radial side of tlie fourth metacarpal bone, and is inserted into 
the first phalanx of the ring finger. 

The adductor of the little finger^ Fig. 120 (s), arises from the 
radial side of the fifth metacarpal bone, and is inserted into 
the first phalanx of the little finger. 

The arrangement of the four dorsal interosseous muscles 
is quite difierent. Two of them are abductors, while the 
other two act on the middle finger. Each one arises by 
two heads. 

The abductor of the forefinger^ Fig. 121 (i), arises from the 
first and second metacarpal bones, and is inserted into the 
base of the first phalanx of the index finger. 



Fig. 120. 



Fig. 121. 





The Palmar Interosseous Mus- 
cles ARE SHOWN IN CONNECTION WITH 

THE Bones of the Right Hand. 



The Dorsal Interosseous Mus- 
cles OF THE Right Hand, and their 
connection with the Tendons op the 
Long Extensor Muscles of the Fin- 
gers, ARE here represented. 



The abductor of the ring finger^ Fig. 121 (4), arises from the 
fourth and fifth metacarpal bones, and is inserted into the first 
phalanx of the ring finger. 

The other two arise ^ Fig. 121 (2, 3), one from the second and 
third, and the other from the third and fourth metacarpal 
bones ; they are both inserted into the first phalanx of the 
middle finger. It will be observed that these are the only 



THE ELBOW-JOINT. 281 

interosseous muscles appropriated to the middle finger. One 
will move it towards the forefinger, and the other towards 
the ring finger. The terms "abductor" and "adductor" 
cannot be applied to these two muscles, unless it is done with 
reference to the median line of the body. 

The tendons of the interosseous muscles are connected to 
those of the long extensors of the fingers, and serve to keep 
the latter applied to the dorsal surface of the phalanges ; 
thus supplying the place of fibrous sheaths. When the 
fingers are flexed, they lose the power of abducting or ad- 
ducting them. They contribute to the strength of the meta- 
carpo-phalangeal articulations. The adductor and abductor 
of the thumb differ from those of the fingers in having no 
attachment to its metacarpal bone. The fibres of the ad- 
ductor pollicis have a direction nearly transverse to the 
axis of the thumb, which adds greatly to the power of this 
muscle. 

The remaining articulations of the upper extremity may 
now be examined. 

The Elbow-joint is formed by the humerus above, and 
the ulna and radius below. The radius and ulna also 
articulate with each other so as to form a movable joint. 
The articular surface of the humerus is adapted to flexion 
of the forearm, and, at the same time, allows the radius to 
rotate on the ulna. Thus it will be seen that this articula- 
tion admits of two distinct movements. It contains only 
one synovial membrane, which lines the inner surface of the 
parietes of the joint. The ligaments are the following : — 

The External Lateral Ligament, Fig. 123 (4), arises 
from the external condyle of the humerus, passes downwards, 
and is inserted into the annular ligament. 

The Internal Lateral Ligament, Fig. 122 (2), arises 
from the internal condyle of the humerus; its fibres diverge 
as they pass downwards to be inserted into the base of the 
coronoid process of the ulna. 

The Anterior Ligament, Fig. 123 (7), is thin and mem- 
branous. Its fibres arise from the margin of the fossa for 
the reception of the coronoid process of the ulna, pass 
downwards in front of the joint, and are inserted into the 

2-1-^- 



282 



THE UPPER EXTREMITY. 



coronoid process, and tlie annular ligament. Tlie removal 
of this ligament affords a very good view of the interior of 
ther joint. 



Fig. 122. 




Fig. 123. 




An Internal View of the Elbow- 
Joint. — 1. The anterior ligament. 2. 
The internal lateral ligament. 3. The 
coronary ligament. 4, The ligamentum 
teres. 5. The interosseous ligament. 
6. The internal condyle, which conceals 
the posterior ligament behind. 



An External View of the Elbow- 
Joint. — 1. The humerus. 2. The ulna. 
3. The radius. 4. The external lateral 
ligament. 5. The coronary ligament. 
6. The insertion of the coronary Jiga- 
ment at the posterior part of the lesser 
sigmoid cavity of the ulna. 7. The an- 
terior ligament. 8. The posterior liga- 
ment. 9. The interosseous ligament of 
the forearm. 



The Posterior Ligament, Fig. 123 (s), consists of but 
little more than condensed areolar tissue. The fibres which 
it contains pass in different directions between the humerus 
and the ulna. 

The Annular or Orbicular Ligament, Fig. 122 (3), sur- 
rounds the cervix of the radius. It is attached to the extre- 
mities of the small sigmoid cavity of the ulna. The synovial 
membrane is prolonged from the upper part of the joint 



THE ELBOW-JOINT. 283 

downwards between this ligament and tlie cervix. Thus the 
cervix of the radius, as well as the head, it will be observed, 
is covered with synovial membrane. This should be noticed 
with reference to the occurrence of fracture in this part of the 
radius. 

The EouND or Oblique Ligament, Fig. 122 (4), consists 
of a small fasciculus, which extends from the coronoid pro- 
cess obliquely downwards, to be inserted into the radius, just 
below its tubercle. 

The Inteeosseous Ligament or Membrane, Fig. 122 (5), 
is composed of fibres which extend from the inner border of 
the shaft of the radius obliquely downwards to the opposite 
border of the ulna. It gives attachment on both of its sur- 
faces to muscles, and is perforated for the passage of vessels 
and nerves. 

The radius and ulna, at their inferior extremities, are con- 
nected to each other by a Fibro-Cartilage, Fig. 125 (s), 
which extends from the styloid process of the ulna to the 
inner border of the radius, between its carpal and ulnar arti- 
cular surfaces. The anterior and posterior borders of this 
fibro -cartilage are attached to the radio-carpal ligaments. 
The synovial membrane between the radius and ulna is 
sometimes called the sacciform membrane or ligament^ Fig. 
125 (1). It is strengthened by anterior and posterior fibres, 
which pass from one bone to the other. 

The radius and ulna are joined to the carpus by an ex- 
ternal and an internal lateral, and an anterior and a posterior 
ligament. 

The External Lateral Ligament, Fig. 121 (-1), arises 
from the styloid process of the radius, and is inserted into 
the scaphoides and trapezium, and the annular ligament. 

The Internal Lateral Ligament, Fig. 124 (5), arises 
from the styloid process of the ulna, and is inserted into 
the cuneiform and pisiform bones. 

The Anterior Ligament, Fig. 12-1 (3), arises from the 
anterior border of the lower end of the radius, and from the 
ulna, and is inserted into the scaphoid, souiiluiuir, and cunei- 
form bones. 

The Posterior Ligament arises from the radius and ulna 



284 



THE UPPER EXTREMITY. 



behind, and is inserted into the semilunar and cnneiform 
bones. 

Fig. 124. 

The Ligaments of the Anterioh Aspect of 
THE Wrist and Hand. — 1. The lower part of the 
interosseous membrane. 2. The anterior inferior 
radio-ulnar ligament. 3. The anterior ligament of 
the wrist joint. 4. Its external lateral ligament. 
5. Its internal lateral ligament. 6. The palmar 
ligaments of the carpus. 7. The pisiform bone 
with its ligaments. 8. The ligaments connecting 
the second range of carpal bones with the meta- 
carpal and the metacarpal with each other. 9. 
The capsular ligament of the carpo-metacarpal 
articulation of the thumb. 10. Anterior ligament 
of the metacarpo-phalangeal articulation of the 
thumb. 11. One of the lateral ligaments of that 
articulation. 12. Anterior ligament of the meta- 
carpo-phalangeal articulation of the index finger; 
this ligament has been removed in the other 
fingers. 13, Lateral ligaments of the same articu- 
lation; the corresponding ligaments are seen in 
the other articulations. 14. Transverse ligament 
connecting the heads of the metacarpal bones of 
the index and middle fingers ; the same ligament 
is seen between the other fingers. 15. Anterior 
and one lateral ligament of the phalangeal articu- 
lation of the thumb. 16, 16. Anterior and lateral 
ligaments of the phalangeal articulations of the 
index finger ; the anterior ligaments are removed 
in the other fingers. 




The carpus is composed of eight bones, arranged in two 
rows ; there being four in each row. The bones in the upper 
row, except the pisiform, are connected together by two 
dorsal and two palmar transverse ligaments^ and also by two 
interosseous fihro-cartilages. The pisiform is connected by a 
capsular ligament to the cuneiform, and by ligamentous fibres 
to the unciform and fifth metacarpal bone. The bones of the 
lower row are joined together by three dorsal^ and three palmar 
transverse ligaments^ and two interosseous fihro-cartilages. 

The two rows are connected to each other by dorsal and 
palmar, and external and internal lateral ligaments. The dor- 
sal and palmar ligaments consist of fibres which pass ob- 
liquely from the bones of one row to those of the other. 

The external lateral ligament extends from the scaphoid to 
the trapezium. The internal lateral ligament connects the 
cuneiform and unciform bones. 



THE LIGAMENTS OF THE HAND. 



285 




The trapezium is connected to the metacarpal bone of the 
thumb bj a capsular ligament. This articulation allows to 

Fig. 125. 

A Diagram showing the disposition 
OF THE five Synovial Membranes of 
THE Weist-Joint. — 1. The sacciform mem- 
brane. 2. The second synovial membrane. 
3, 3. The third, or large synovial mem- 
brane. 4. The synovial membrane between 
the pisiform bone and the cuneiform. 5. 
The synovial membrane of the metacarpal 
articulation of the thumb. 6. The lower 
extremity of the radius. 7. The lower 
extremity of the ulna. 8. The inter- 
articular fibro cartilage, s. The scaphoid 
bone. L. The semilunar, c. The cunei- 
form ; the interosseous ligaments are seen 
passing between these three bones and 
separating the articulations of the wrist 
(2) from the articulation of the carpal 
bones (3). p. The pisiforme. t. The 
trapezium. 2t. The trapezoides. M. The 
OS magnum, u. The unciform interos- 
seous ligaments are seen eonnecting the 
OS magnum with the trapezoides and unci- 
form. 9. The base of the metacarpal bone 
of the thumb. 10, 10. The bases of the 
other metacarpal bones. 

the thumb a great degree of motion. The metacarpal bones 
of the fingers are connected to the carpus by dorsal and pal- 
mar ligaments. The former are stronger than the latter. 

The metacarpal bones are united at their carpal extremi- 
ties by dorsal and palmar transverse ligaments^ and also by 
interosseous fibres. Their phalangeal extremities are connected 
to each other by three loose transverse fibrous bands. 

Each metacarpal bone is connected to its corresponding 
phalangeal bone by an anterior and tivo lateral ligaments. 
The anterior ligament is joined to the lateral ligaments on its 
sides. Anteriorly it is grooved for the tendons of the flexor 
muscles of the fingers, the sheaths of which are attached 
to it on each side of the groove. The lateral ligaments of 
the thumb are very strong, and sometimes contain sesamoid 
bones. 

The articulations of the phalangeal bones have each an 
anterior and ttco lateral ligaments. They require no particular 
description. 

The synovial membranes, Fig. 125, about the wrist should 
be carefully examined. There are five distinct capsules. 



286 DISSECTION OF SPINAL CANAL AND CONTENTS, 

The large extent of articular surface in the carpus, is deser- 
ving of notice. The different joints should be opened by the 
student. This can be done after the soft parts have been 
dissected, without injuring the bones. 



Sect. Y. — Dissection of the Spinal Canal and its 

Contents. 

To lay open the spinal canal, the soft parts which cover the 
lamellae of the vertebra should be entirely removed. When 
this has been done, a mallet and sharp chisel may be used 
for dividing the lamellae on each side of the spinous processes ; 
or, instead of the chisel, a saw may be used for this purpose. 
Bone-nippers will also sometimes be found useful. The liga- 
mentous attachments must be severed with the scalpel. The 
vertebral column should be made as convex, posteriorly, as 
possible, by placing blocks underneath the subject. If the 
calvaria and the posterior part of the occipital bone have 
been removed before opening the canal, the student will be 
able to obtain a very satisfactory view of the relations of the 
parts in the spinal canal to those in the cranial cavity. 

The contents of the spinal canal are the following : The 
dura mater, the arachnoid, the pia mater, the spinal cord, 
the roots of the spinal nerves, the spinal ganglia, and the 
intra-spinal vessels. 

The DuEA Mater of the cord has the same structure as 
that of the brain, with which it is continuous through the 
occipital foramen; it has not, however, the same uses. It 
does not form an internal periosteum to the walls of the 
spinal canal, nor does it furnish sinuses for the transmission 
of venous blood, or send off processes to support different 
parts of the spinal marrow. 

It is separated from the parietes of the canal, more or less, 
by a soft, reddish, adipose and areolar tissue, and by plexuses 
of veins. It has fibrous attachments to the posterior common 
spinal ligament. Its external surface is generally smooth. 
In size it corresponds to the cord, being larger in the neck 
and the loins than elsewhere. It gives off processes, which 
surround the nerves as they pass through the intervertebral 
foramina. The lower part of it is divided into tubular pro- 



SPINAL CANAL AND CONTENTS. 287 

longations, whicli contain the sacral nerves as thej extend 
some distance in the canal before leaving it. Below it sends 
down a small fibrous cord, which is attached to the walls of 
the lower part of the sacral canal. It is more fixed in the 
anterior than in the posterior part of the canal, bj its attach- 
ments to the posterior common spinal ligament. 

The Aeachnoid lines the internal surface of the dura 
mater, and also invests the cord. It is exposed by slitting 
open the dura mater in the median line, through its whole 
length. It is continuous with the arachnoid of the brain, 
to which it is similar in structure and function. The 
visceral portion is connected to the parietal by tubular pro- 
longations around the roots of the nerves. 

It is separated from the pia mater by the sitbarachnoid 
space^ which is occupied by cellulo-fibrous tissue and a fluid. 
The fibrous structure is most abundant in the middle line 
behind, where it forms an imperfect septum. If this space be 
punctured in a living animal, the subarachnoid fluid escapes 
in a jet, causing, for a time, stupefaction of the animal. The 
principal use of this fluid is, probably, to protect the spinal 
marrow. A serous exhalation takes place from both surfaces 
of the arachnoid membrane, where it invests the cord. 

The Pia Mater surrounds and adheres closely to the 
spinal cord. It is continuous with that of the brain, from 
which, however, it differs in structure, being more dense and 
fibrous, and less vascular. It sends prolongations into the 
anterior and posterior fissures of the cord, and also along the 
roots of the nerves. It terminates below, after furnishing 
sheaths for the nerves, in a fibrous cord, which descends to 
the sacrum, where it is attached to the dura mater. 

The LiGAMENTUM Denticulatum, Fig. 126 (i 9), is found on 
each side of the cord, and between the anterior and posterior 
roots of the nerves ; it reaches from the occipital foramen to 
the first lumbar vertebra. Its inner border is straight, and 
appears to be blended with the pia mater ; while its outer 
border presents a series of tooth-like processes, which are 
attached to the dura mater in the spaces between the foramina 
which give exit to the nerves. In the upper part of the 
canal the spinal accessory nerve lies behind it. The serrated 
processes number twenty one or two. It separates the roots 
of the nerves and prevents lateral movement of the cord. 



288 DISSECTION OF SPINAL CANAL AND CONTENTS. 



14^ 



The intra-spinal vessels consist of those wMcli supply the 
walls of the canal, and the cord, inclnding its 
Fig. 126. membranes. 

^2;Tin The Arteeies are derived from the verte- 

bral, the intercostal, the Inmbar, and the lateral 
sacral. Those which are denominated the a7i- 
terior and posterior spinal arteries arise from the 
vertebral near the occipital foramen. There 
are two posterior and one anterior. They sup- 
ply, principally, the upper part of the cord. 
The remaining arteries enter the canal through 
the intervertebral foramina, and reach the cord 
by passing along the roots of the nerves. 
There are usually three or four branches much 
larger than the others. These form a free 
anastomosis with the anterior and posterior 
spinal arteries. 

The Yeins of the cord leave the canal by 
passing through the occipital and interverte- 
bral foramina. Those which enter the cranial 
cavity terminate in the sinuses of the dura 
mater ; the others are connected with the sacral, 
the lumbar, the intercostal, and the vertebral 
veins. There are several plexuses of veins in 
the spinal canal outside of the dura mater. 
These are designated the anterior^ the lateral^ 
and the posterior plexuses. There are two 
plexuses which extend the whole length of the 
canal. They are situated on the posterior sur- 
face of the bodies of the vertebrse, one on each 
side of the posterior common ligament. These 
plexuses all communicate freely with each 
other. 

IR 

An Anterior View op the Spinal Marrow, seen in its Whole Length, after 
Removal from the Spinal Canal. — 1. Lines indicating the corpora pyramidalia. 
2. Corpora olivaria. 3. Anterior face of the spinal marrow. 4. Anterior roots of 
the cervical spinal nerves. 5. Anterior roots of the dorsal nerves. 6. Anterior 
roots of the lumbar nerves. 7. Anterior roots of the sacral nerves. 8, 9, 10, 11. 
The anterior and posterior roots of the spinal nerves, united to pass out of the dura 
mater. 12. Dura mater of the medulla spinalis. 13. Ganglia on the cervical 
nerves. 14. Ganglia on the dorsal nerves. 15. Ganglia on the lumbar nerves. 16. 
Ganglia on the sacral nerves. 17. Cauda equina. 18. Sub-occipital nerve. 19. 
Ligamentum denticulatum. 



DISSECTION OF SPINAL CANAL AND CONTENTS. 289 



The Medulla Spinalis, or Spinal Cord. 



Fig. 127. 



The spinal cord, Fig. 126, extends from tlie occipito- 
atlantoid articulation, to the first lumbar vertebra; being 
from sixteen to eighteen inches in length. It is much smaller 
than the spinal canal. It is not of equal size throughout its 
whole length. Those portions which correspond to the roots 
of the nerves that supply the upper and lower extremities, 
are the largest. It terminates below in the cauda equina^ Fig. 
126 (17), which consists of nervous cords. 

The cord presents, externally, an anterior and a posterior 
median fissure^ Fig. 128, which 
divide it, externally, into two 
distinct lateral columns. The 
pia mater enters these fissures. 
The anterior one is the widest, 
while the posterior is the 
deepest. A lateral fissure is 
observed where the posterior 
roots of the nerves are attach- 
ed to the cord. This fissure 
divides each half of the cord 
into an antero-lateral, and a 
posterior column. Another 
lateral fissure has been de- 
scribed, corresponding to the 
anterior roots of the nerves; 
this, however, is scarcely per- 
ceptible. 

When a transverse section 
of the cord is made, each half is seen to consist, internally, of 
gray substance. Fig. 128. This is arranged so as to present 
a semilunar form, the cornua of which correspond to the 
anterior and posterior roots of the nerves. The posterior 
cornu reaches the external surface of the cord, but the an- 
terior, which is the shortest and thickest of the two, does not. 
From this arrangement of the gray substance each half of 
the cord may be said to consist of three columns, the antero- 
lateral being divided into two by the anterior cornu. Vesicu- 
lar matter exists in both cornua, but is most abundant in the 
25 




a View of a Small Portion of 
THE Spinal Marrow, showing the 
Origins of some of the Spinal 
Nerves. — 1. The anterior or motor 
root of a spinal nerve. 2. The pos- 
terior or sensor root of a spinal 
nerve. 3. The ganglion connected 
with the latter. 



290 



MEDULLA SPINALIS. 



posterior. Tlie gray substance in tlie anterior cornn has been 
called the substantia gelatinosa; and tbat in the posterior, the 
substantia spongiosa. 

The two halves of the cord are nnited by a gray commissure 
at the bottom of the posterior median fis- 
sure, and a white commissure at the bottom 
of the anterior median fissure. 

The relative proportions of the gray and 
white substance vary somewhat in differ- 
ent sections of the cord. 

The precise manner in which the spinal 
nerves are connected with the substance 
of the cord, is not well understood. The 
anterior and posterior roots approach each 
other as they proceed from the cord to the 
foramina in the dura mater. Fig. 126 (s, 9, 
10, 11), through which they pass sepa- 
rately. The posterior root or fasciculus of 
each nerve enters a ganglion^ Fig. 127 (3), 
in the intervertebral foramen ; and almost 
immediately after passing through the 
ganglion it joins the anterior fasciculus, 
and is inclosed with it in the same neuri- 
lemma, which is derived from the dura 
mater. The fasciculi increase in length 
from above downwards before they per- 
forate the fibrous sheath of the cord. 

The posterior roots are sensor^ and are 
larger than the anterior, which are motor^ 
Fig. 127 (1, 2). Each set is supposed to 
contain filaments, which belong to both 
the excito-motor and the cerebro-spinal 
system of nerves. 




Transverse Section of the Spinal Cord. — a. Immediately below the decussa- 
tion of the pyramids, b. At middle of cervical bulb. c. Midway between cervical 
and lumbar bulbs, d. Lumbar bulb. e. An inch lower, r. Very near the lower 
end. a. Anterior surface, p. Posterior surface. The points of emergence of the 
anterior and posterior roots of the nerves are also seen. 



DISSECTION OF THE THORAX. 291 



CHAPTER II. 

Sect. I. — Dissection of the Thorax. 

The thorax is situated between the neck above, the abdo- 
men below, and the upper extremities laterally. The solid 
parietes of the thoracic cavity consist of the sternum and 
costal cartilages in front, of the ribs laterally, and the dorsal 
vertebrae, with the posterior extremities of the ribs behind. 

The shape of the thorax is that of a truncated cone, indented 
behind by the spinal fossae. Its hase is oblique, sloping from 
the xiphoid cartilage downwards and backwards to the first 
lumbar vertebra. Its apex is also oblique, but from before 
upwards and backwards to the last cervical vertebra ; hence 
the vertical diameter of the thoracic cavity is much greater 
behind than before. 

The spaces between the ribs are occupied by aponeurosis 
and the intercostal muscles, which are perforated by branches 
of the intercostal arteries and nerves, and by branches of the 
internal mammary arteries. 

The upper orifice of the thoracic cavity is broader trans- 
versely than from behind forwards. Its boundaries are 
formed, in front, by the upper border of the sternum, on each 
side by the first rib, and behind, by the first dorsal vertebra. 

It transmits the oesophagus, the trachea, the thoracic duct, 
the pneumogastric, phrenic, and sympathetic nerves, and 
the large arteries and veins of the head, neck, and upper 
extremities ; the superior intercostal and internal mammary 
arteries, with the recurrent laryngeal nerves, also pass through 
it. Besides the parts just enumerated, and the thoracic fascia, 
which surrounds and connects them together, the apex of each 
lung, with the pleura and several muscles, are included in 
this opening. 

The lower orifice is four or five times larger than the upper, 
and is liable to much greater variation in size. It is bounded 
in front by the xiphoid cartilage, laterally by the lower six 



292 DISSECTION OF THE THOEAX. 

ribs and tlieir cartilages, and behind, by the last dorsal vertebra. 
Its circumference embraces the upper abdominal viscera, as 
the liver, the stomach, the spleen, kc. The diaphragm, which 
forms the septum between the abdominal and thoracic cavi- 
ties, is attached to nearly the whole of its margin. The ceso- 
phagus, the thoracic duct, the pneumogastric, sympathetic, 
and splanchnic nerves, the aorta, the ascending vena cava, 
and the azygos vein, pass through the diaphragm. 

The intercostal muscles should be examined before the 
cavity of the thorax is opened. They consist of two sets, 
the internal and external. 

The ExTEEXAL IxTEECOSTALS. Tig. 1-17 (4). extend from 
the vertebral articulations of the ribs to the costal cartilages. 
They arise from the outer lip of the lower border of each 
rib, except the last, pass obliquely downwards and for- 
wards, and are inserted into the corresponding lip of the 
upper border of each rib, immediately below their origin. 

The IxTEEXAL IXTEECOSTALS, Tig. 11:7 (o), extend from the 
angles of the ribs to the sternum. They arise from the inner 
lip of the lower border of each rib and its cartilage, except 
the last, pass dov-mwards and somewhat backwards, and 
are inserted into the upper border of each rib, below their 
origin. An ajjoneurosis extends from the external to the ster- 
num, and also from the internal to the costo-vertebral articu- 
lations. A considerable portion of each of the intercostal 
muscles is tendinous, or aponeurotic. Their fibres have the 
same direction, respectively, as those of the external and in- 
ternal oblique muscles of the abdomen. The intercostal arte- 
ries and nerves pass between them. They act as muscles of 
inspiration or expiration, according as the first rib, or the 
lower ribs be fixed. The crossing of them adds to the strength 
of the thoracic parietes. 

The cavity of the thorax may now be opened for the study 
of its contents. This may be done in several ways. If it be 
wished to preserve the skeleton, the student can obtain a very 
good idea of the thoracic viscera and their relations by adopt- 
ing the following method : — 

Saw through the sternum in the median hne, taking care 
not to injure the soft parts anderneath it. Then divide the 
intercostal muscles, and separate the costal cartdages, on each 



THE THORAX. 293 

side, from the ribs ; the pleura may be divided at the same 
time, as this will not interfere with the study of it afterwards.-^ 
By carefully separating the two halves of the sternum, a 
space will be observed behind it, bounded laterally by the 
pleura ; and, by raising the cartilages on each side, the man- 
ner in which this space is formed will be readily understood, 
by observing that each pleura is reflected from the posterior 
surface of the sternum backwards. It will be noticed that, 
as the pleurse leave the sternum, they are, in the centre, very 
nearly in apposition, leaving scarcely any space between them, 
while above and below they are separated a short distance 
from each other. The left pleura is reflected from the lower 
part of the sternum obliquely downwards, and to the left 
side. 

One half of the sternum, with the cartilages attached to it, 
may now be raised, commencing at its upper extremity, and 
reflected downwards over the abdomen without detaching it 
from the diaphragm. In raising it, the origin of the sterno- 
thyroideus, and sometimes that of the sterno-hyoideus, the 
internal mammary artery, the triangularis sterni muscle, and 
the intercostal nerves, will be seen. 

The Triangularis Sterni Muscle is situated behind the 
sternum and costal cartilages. It arises from the side of the 
sternum and xiphoid cartilage, and some of the costal carti- 
lages close to the sternum. It divides into several digitations, 
which are inserted into the second, third, fourth, fifth, and 
sixth ribs. The lower fibres have nearly a transverse direc- 
tion, and are continuous with the transverse muscle of the 
abdomen ; the upper fibres pass obliquely upwards and out- 
wards. Its action is to draw down, or to fix the costal carti- 
lages. 

The Internal Mammary Artery arises from the sub- 
clavian opposite to the supra-scapuhxr, and passes obliquely 
downwards behind the sternal extremity of the clavicle and 
cartilage of the first rib, where it enters the cavity of the 

' a partial view of tlie contents of the thoracic viscera may be obtained 
by simply dividing the sternum in the median line, and separating the two 
halves by means of dilators made for the purpose, or b}' any means which 
may be most convenient. To make a thorough examination of the contents 
of the thoracic cavity, it is necessary to cut away, more or less, the ribs. 

25^ 



294 DISSECTION OF THE THORAX. 

thorax. In this part of its course, the phrenic nerve crosses 
it superficially from ^thout inwards. Its course in the thorax 
is nearly parallel with, and about one-third of an inch from, 
the border of the sternum. It is situated between the costal 
cartilages in front and the pleura and triangularis sterni mus- 
cle behind. At the sixth intercostal space it divides into two 
branches, external and internal. 

The internal division^ which is generally regarded as a con- 
tinuation of the artery, passes beneath the cartilage of the 
seventh rib, and pierces the sheath of the rectus abdominis 
muscle. It supplies the upper and anterior parietes of the 
abdomen, and inosculates ^ith branches of the epigastric, thus 
connecting the external iliac and subclavian arteries. 

The external hranch^ or mu^sculo-xjhrenic. goes obliquely 
downwards and outwards to the eleventh intercostal space, 
giving off, in its course, branches to the diaphragm, and to 
the intercostal and abdominal muscles. Its branches inoscu- 
late, with the lower intercostal arteries, from the aorta. 

The internal mammary artery, before it divides, gives off 
the following branches : — 

The anterior intercostals are directed outwards, in the inter- 
costal spaces; they inosculate v.'ith the aortic intercostals. 
There are frequently two in each space. 

The anterior^ ot jjerf orating Iranches^ pierce the internal in- 
tercostal and pectoralis major muscles. They are distributed 
to these muscles, and to the integuments and mammary gland, 
and inosculate with branches from the axillary artery. 

The mediastinal hranches are distributed to the remains of 
the thymus gland, and other parts in the mediastinal space. 

A branch — comes nervi phrenici — accompanies the phrenic 
nerve to the diaphragm, gi^"ing branches in its course to the 
pericardium. The internal mammary artery has two vencB 
comites. 

The AxTEEiOR CuTAXEOUS Beaxches of the upper inter- 
costal nerves may be seen where they perforate the internal 
intercostal and pectoralis major muscles near the sternum, to 
reach the integument. 

There are three serous sacs in the thoracic cavity — one for 
each lung, and one for the heart. The necessity of each of 
these organs having appropriated to it a serous membrane 



THE PLEUEA. 295 

will be understood when it is considered tliat they are sub- 
jected to more or less motion. Each sac is divided into a 
visceral and a parietal portion. The first is applied closely 
to the external surface of the organ, while the other lines 
the inner surface of the cavity which contains it. Thus two 
smooth surfaces are opposed to each other, which are con- 
stantly lubricated with serum, so that no friction is caused 
by their movements upon each other. 



The Pleura. 

The student should now carefully trace the reflections of 
the pleura for himself, and observe its relations to the con- 
tiguous parts, and to the external surface of the body. The 
pleural cavity has been exposed by separating the costal car- 
tilages from the ribs, and raising them on one side with the 
corresponding half of the sternum. It will be observed 
that as the pleura is reflected from the posterior surface of 
the sternum, it proceeds almost directly backwards to the 
vertebral column. 

The corresponding portions of the two pleurae form a sep- 
tum between the pleural cavities, called the mediastinum. The 
lower part of this septum is inclined somewhat to the left 
side on account of the position of the heart. That portion 
of each pleura concerned in forming the mediastinum is 
called the pleura mediastinalis. As this is traced from the 
sternum backwards, it will be found in the upper part of the 
thorax to pass almost directly to the vertebra3, while in the 
middle and lower parts it is reflected outwards over the 
pericardium, to which it closely adheres, except where it 
covers the phrenic nerve. As it proceeds backwards it is, 
near the middle of the mediastinum, reflected round the root 
of the lung, from which it is extended over the entire lung, 
forming the pleuo^a puhnonalis. 

In the lower part it forms a fold extending from the root 
of the lung to the diaphragm, called the ligameiUuin latum 
pulmonis. This fold is of a triangular shape, with the apex 
towards the root of the lung. If the lungs be drawn for- 
wards it will be seen that the pleurae approach each other as 



296 DISSECTION OF THE THORAX. 

they are reflected from tlie roots of the lungs and the peri- 
cardium to the vertebral column. 

The pleura mediastinalis is continuous below, with the 
pleura dia])hragmatica^ and laterally with the pleura costalis. 
The former lines the thoracic surface of the diaphragm ; the 
latter covers the inner surface of the ribs and intercostal 
spaces, the internal mammary and intercostal arteries, the 
splanchnic, sympathetic and intercostal nerves, and the dor- 
sal ganglia of the sympathetic. 

The pleura is prolonged from half an inch to an inch above 
the first rib, where it covers the posterior surface of the lower 
part of the scalenus anticus muscle, and the subclavian artery. 
It usually extends somewhat higher on the right side than 
on the left. Small masses of fat, similar to the appendices 
epiploic£e on the colon, are sometimes observed on the medias- 
tinal and diaphragmatic portions. 

The pleura pulmonalis lines the fissures which separate the 
lobes of the lung. It is very thin and elastic. The inner or 
fibrous layer is connected with the parenchjmia of the lung. 
The air will generally escape through it from the cells when 
the lungs are removed from the thorax and inflated. The 
fibrous layer of the costal pleura is thicker than that of either 
of the other portions, and more easily detached from the 
subjacent tissues. 

The shape of the cavity formed by the parietal pleura is 
the same as that of the lung which fills it. The left one is 
longer than the right, but not so broad. Abscesses rarely 
open into the pleural cavities, either from the lungs or from 
the surrounding parts. 

Having examined the pleura, the student should now pro- 
ceed to the study of the contents of the 'mediastinal space. 

The boundaries of this space are on each side the medias- 
tinal pleura, in front the sternum, behind the vertebral 
column, below the diaphragm, and above the upper orifice of 
the thorax. To facilitate the study of the organs, especially 
of their position in the thorax, contained in this space, it 
will be found convenient to divide it into four parts ; and as 
the heart is the principal organ in point of size in it, it 
naturally forms the basis of this division. 

Observing its position, or that of the pericardium, the 
student will have no difticulty in understanding these di- 
visions. 



THE PLEUEA. 



297 



The anterior is situated between tlie heart and the ster- 
num ; the posterior between the heart and the spinal 
column; the superior^ between the heart below, and the 
upper orifice of the thorax above, the sternum in front, and 
the spinal column behind; while the heart and pericar- 
dium occupy the middle. The mediastinal pleurae form 
the lateral boundaries of each of these divisions. Thus 
it will be seen that while the heart is below the supe- 
rior mediastinum, and in the middle, it is directly between 
the anterior and posterior mediastina, as they are usually 
termed. The diagram. Fig. 129, representing a section of 
the thorax in the median line, shows 
the relative positio;n of the four sub- 
divisions of the mediastinal space. 

The anterior mediastinum has been 
exposed by the longitudinal section, 
and removal of the sternum. It con- 
tains the lower portion of the remains 
of the thymus gland, areolar tissue, 
and some fat. As the diaphragm is 
deficient behind the xiphoid cartilage, 
this space is separated from the cavity 
of the abdomen only by areolar tissue, 
which accounts for pus sometimes 
passing from it into that cavity. The 
cavity of the pericardium can be 
reached, as in paracentesis pericardii, 
through this space, without opening 
either of the pleural cavities. 




Diagram of the Thoracic 
Mediastina. — a, 6. Dorsal 
vertebrae, c. Sternum. d. 
Diaphragm, or lower orifice of 
the thorax, e. Upper orifice of 
the thorax. 1. Anterior medi- 
astinum. 2. Middle mediasti- 
num ; figure is on the heart. 
3. Posterior mediastinum. 4. 
Superior mediastinum. 



The Phrenic Nerves should be 
noticed before examining the pericar- 
dium. They will be found passing 
through the middle mediastinum, from 
above downwards on the sides of the pericardium, between 
it and the pleura. They can usually be distinctly seen with- 
out dissecting off the pleura. The left is somewhat longer 
than the right, on account of the projection of the pericar- 
dium to the left side. They descend to the diaphragm, and 
ramify on its upper surface, between it and the pleura^ ; some 
filaments pass through the muscle, and ramify on its abdo- 



298 DISSECTION OF THE THOEAX. _ 

minal surface, where an anastomosis is formed between the 
two nerves. They are said, also, to anastomose with the 
pneumogastric nerve and solar plexus. 



The Pekicardium. 

The Pericardium is a fibro-serous membrane, which sur- 
rounds the heart. To obtain a good view of it, the areolar 
tissue, and fat in the anterior mediastinum should be removed. 
It will be found to have a conical form^ with the base down- 
wards, and the apex upwards. . The hase is closely connected 
anteriorly, to the cordiform tendon of the diaphragm, from 
which it cannot, without difficulty, especially in the adult, be 
separated. In consequence of this attachment, but little 
motion is allowed to the lower part of the pericardium. The 
apex terminates above by being blended with the thoracic 
fascia, the external layers of the vena cava, aorta, and pulmo- 
nary artery, some distance from the base of the heart. Late- 
rally it is in relation with the pleurae and phrenic nerves. In 
front it corresponds to the sternum, and the cartilages of the 
fifth, sixth, and seventh ribs, from which it is separated by the 
anterior mediastinum and the pleuree, and the left lung, which 
is excavated for the reception of the heart. Posteriorly it 
forms the anterior wall of the posterior mediastinum. 

Its. fibrous or external lamina is perforated by all the 
large vessels which leave or enter the heart. These are the 
two venge cavae, the aorta, the pulmonary artery, and the four 
pulmonary veins. 

The pericardium may now be opened by making a longi- 
tudinal, and, if necessary, a transverse incision. The inner 
or serous layer presents the same appearance as other serous 
membranes. It lines the internal surface of the fibrous layer, 
and is reflected from it upon the large vessels at the base 
of the heart, and from them over the heart itself. 

It is reflected from the fibrous layer to the vessels, where 
that layer joins their outer coats. This takes place upon the 
vena cava descendens, near the entrance of the vena azygos. 
At first it is limited to the anterior surface of this vessel, but 
nearly surrounds it at the auricle. It is reflected to the aorta 
at its arch, and to the pulmonary artery at its bifurcation ; 
and, as it descends to the ventricles, it completely invests 



THE HEART. 299 

those vessels, except wliere they are in apposition. It covers 
anteriorly the pulmonary veins between the left auricle and 
their divisions into branches. The vena cava ascendens is 
only partly invested by it. Where it is reflected over the 
vessels, it forms between them depressions or culs-de-sac. 

When the heart is empty, it lies loosely in the cavity of 
the pericardium, but when the former is full, or distended, it 
just fills the latter. When the blood escapes from the cavities 
of the heart, or from the great vessels at its base into the 
pericardium, it destroys life by interfering mechanically with 
the action of the heart. 

The fibrous layer of the pericardium is composed of fibres 
crossing in different directions ; a large proportion of them, 
however, are longitudinal. This membrane is very strong 
and slightly elastic. Although the heart, when distended, 
just fills the pericardium, yet the latter is sometimes in- 
creased to two or three times the size of the former, by the 
gradual accumulation of fluid in it. 

The student should observe the effect such a collection 
would have by making pressure iipon, or by causing dis- 
placement of, surrounding organs. Fat is not unfrequently 
deposited in considerable quantity between the muscular 
fibres of the heart and the serous layer which invests it. 



The Heaet. 

It is better that the student should examine the heart be- 
fore it is removed from the thorax ; or, at least, the more 
important parts of it. Before proceeding to its dissection, he 
should carefully observe its position in the thoracic cavity, 
its relations to contiguous parts, its external appearance, and 
the situation of its different compartments, the auricles and 
ventricles. 

It is situated, as will be seen, in the lower and central 
part of the thorax, between the lungs, and resting on the 
diaphragm. Its form is conical, presenting a base, body, and 
apex. The hase looks upwards, backwards, and to the right 
side ; it corresponds, in front^ to an oblique line extending 
across the sternum from the third intercostal space on the 
left side to the fourth and fifth on the right side; and hchind^ 
to the fifth, sixth, and seventh dorsal vertebras, from Avhich it 



300 DISSECTION OF THE THORAX. 

is separated by tlie contents of the posterior mediastinum. 
The a'pex looks forwards and to the left side ; being nearly 
opposite to the junction of the sixth rib with its cartilage. 
The axis of the heart has a direction from right to left, from 
above downwards, and from behind forwards. 

Before displacing the heart, the following points should be 
carefully observed : — 

The three great vessels, vena cava descendens, aorta, and 
pulmonary artery, will be seen at its base. The vena cava^ 
Fig. 130 (5), descends on the right side to enter the upper 
part of the right auricle. The pulmonary artery^ Fig. 130 
(13), prominent at its commencement, ascends from the su- 
perior and left portion of the right ventricle. The aorta^ 
Fig. 130 (e), at first deep seated and partly concealed by the 
pulmonary artery, ascends between the other two. The right 
auricle, Fig. 130 (1), is applied to the aorta, and the left auricle 
Fig. 130 (2), to the pulmonary artery. Only a small portion 
of the left auricle can be seen while the heart is in situ; the 
pulmonary artery, the aorta, and a considerable portion, of the 
right auricle being situated in front of it. 

A large part of the right auricle^ Fig. 130 (1), can be seen 
without disturbing the position of the heart, of which it forms 
the upper and right portion. It presents anteriorly, and to 
the right, a smooth shining convex surface, which corre- 
sponds mainly to the right lung and to the diaphragm, 
just above which it is joined by the vena cava ascendens. 
It is separated, superficially, from the right ventricle by a 
groove, which is occupied by the anterior coronary artery 
and vein, and corresponds to the auriculo -ventricular septum. 

The right ventricle^ Fig. 130 (3), forms a large part of the 
anterior surface of the heart. Its anterior surface, as now 
seen, is convex, and of a triangular shape ; its lower border 
rests on the diaphragm, while its superior left border is sepa- 
rated from the left ventricle by a groove. Fig. 130 (11), which 
corresponds to the ventricular septum, and is occupied by 
the posterior coronary artery and vein; its base, as has been 
already observed, corresponds to the right auricle and the 
pulmonary artery. A small portion of the left ventricle^ Fig. 
130 (4), is seen to the left and above the right ventricle. It 
projects lower down than the right, and thus forms the apex 
of the heart. 



THE HEART. 



801 



The heart should now be lifted from the pericardium so 
as to bring into view its remaining surfaces. The inferior 
surface of the right ventricle, Fig. 131 (s), is flat, triangular 
and horizontal; it corresponds to the cordiform tendon of the 
diaphragm. The posterior and left surface of the left ven- 
tricle, Fig. 131 (4), is round, and corresponds partly to the 
diaphragm, and partly to the posterior mediastinum and left 
lung. The ventricles are separated behind by a groove. 
Fig. 131 (] 0), similar to the one noticed in front; it is occu- 
pied by the posterior coronary vessels. 



Fig. 130. 




Fig. 131. 




An Anterior View of the Heart 
IN A Vertical Position, with its 
Vessels injected. — 1. Right auricle. 
2. Left auricle. 3. Right ventricle. 
4. Left ventricle. 6. Descending vena 
cava. 6. Aorta. 7. Left pulmonary 
artery. 8. The arteriainnominata. 9. 
Left primitive carotid. 10. Left sub- 
clavian artery. 11. Anterior cardiac 
vessels in the vertical groove. 12. Pos- 
terior vessels from the transverse 
groove. 13. Main trunk of the pulmo- 
nary artery. 



A Posterior View op the Heart 
IN A Vertical Position, with its 
Vessels injected. — 1. Right auricle. 
2. Left auricle. 3. Right ventricle. 
4. Left ventricle. 5. Ascending vena 
cava. 6. Right posterior pulmonary 
vein. 7. Left posterior pulmonary vein. 
8. End of the left auricle. 9. Great 
coronary vein. 10. Posterior cardiac 
vessels in the vertical groove. 11. 
The same in the transverse groove. 



The posterior surface of the auricles. Fig. 131 (i, 2), is 
convex, and corresponds to the posterior mediastinum; it is 
divided vertically by a groove, wliich corresponds to the au- 
ricular septum, and is separated from the ventricles by 
another groove, which corresponds to the auriculo-ventri- 
cular septum. The pulmonary veins, Fig. 131 (e, i\ may 
26 



802 DISSECTIOX OF THE THOEAX. 

be seen coming from tlie lungs, and entering the left au- 
ricle.^ 

Eeplacing tlie heart in the pericardium, the student should 
now proceed to its dissection, commencing with the Right 
AuEiCLE. Make an incision from the vena cava descendens 
do^vn to the vena cava ascendens, and another transversely 
from this to the left extremity of the auricle. The blood and 
coagula usually found in this cavity must be removed with 
a sponge and water. 

That portion of the auricle between the mouths of the 
ven£e cav^e is called the sinus venosus, ^hile the elongated 
portion on the left is termed the auricula^ or aj^jje-ndix auri- 
culce ; from the shape of the latter the term auricle has been 
applied to the entire cavity. The right portion of the walls 
of the sinus seem to be formed by the junction of the vense 
cava?, and is nearly destitute of muscular fibres. 

The following are -to be observed in the right auricle: 
The tubercle of Lower, the fossa ovalis, the annulus ovahs, 
or isthmus of Yieussens, the valve of Enstachius, the mouth 
of the coronary vein, the valve of Thebesius, the foramina 
of Thebesius, and the musculi pectinati. 

The tubercle of Lower is a smooth rounded projection, 
situated below and a little to the right of the mouth of the 
descending cava. It is formed by a slight thickening of the 
wall, and by the oblique manner in which the vense cavge 
join the auricle. 

The fossa ovalis, Fig. 132, ?*, is a depression situated just 
above the mouth of the ascending cava and on the auricular 
septum. It indicates the position of the/'b/*a7/2e72 ovale in the 
foetal heart, and appears to be formed by a prolongation 
upwards of the posterior wall of the ascending cava. In the 
upper part of this fossa a small valvular opening is frequently 
found in the adult heart, leading into the left auricle ; from 
its oblique dri^ection, probably no intermixture of the blood 
in the auricles takes place through it. 

The annulus ovalis^ or istliraus of Yieussens, Fig. 132, s, con- 
sists of an elevation around the upper and left marg'in of the 
fossa ovalis. In some hearts it is very imperfect. 

' The vessels of the heart cannot be very satisfactorily traced unless they 
are injected: and as this cannot vrell be done in the heart that is intended 
for dissection, another one ivill be required for this purpose. 



THE HEART. 



303 



The valve of Eustachius^ Fig. 132, w, is a duplicature of tlie 
lining membrane of the auricle, extending upwards from tlie 
anterior and inner margin of the mouth of the ascending 

Fig. 132. 




Heart placed with its Anterior Surface Upwards, and its Apex turned 
TO the Right Hand op the Spectator. The Right Auricle and Right Ven- 
tricle ARE Both opened. Parts in Right Auricle. — h. Entrance of vena cava 
superior, which is itself marked d. Inferior cava, marked r, has a probe passed 
through it into the auricle, m. The smooth part of the auricle, o. Musculi peoti- 
nati, seen in the auricular appendix which is cut open. n. Eustachian valve placed 
over the mouth of the inferior cava. i. Fossa ovalis, or vestige of the foramen ovale. 
8. Annulus ovalis. The probe leading from s into the right ventricle passes through 
the auriculo-ventricular opening, v. Mouth of the coronary vein. Parts in the 
Right Ventricle, in which the other end of the probe, from s, appears, a. Cavity of 
conus arteriosus, leading to the mouth of the pulmonary artery k. I. Convex sep- 
tum between the ventricles, c. Anterior segment of the tricuspid valvo connected 
by slender chords, the chorda) tcndinea>, to the musculi papillares e. f. The aorta. 

cava, along the left border of the fossa ovalis. It performs 
no office in the adult heart, and is often dehciont, or scarcely 
perceptible. In the foetal heart it serves to direct the blood 



304 DISSECTION OF THE THOEAX. 

from the ascending cava into tlie left auricle throiigli the 
foramen ovale. 

The mouth of the coronary vein^ Fig. 132, ?;, is placed a little 
to the left of the Eustachian valve. It is partly covered by 
a fold of the lining membrane of the auricle, which is named 
the valve of Thehesius. It prevents the return of the blood 
into the vein when the auricle contracts ; its of&ce, however, 
cannot be very important, as it is often imperfect or wholly 
absent. 

The/oramma of Thehesius are small openings, consisting of 
the mouths of veins, or of mere crypts in the parietes of the 
auricle. They vary in number and in their location. 

The musculi pectinati^ Fig. 132, o, are muscular fasciculi, 
which extend in parallel lines from the auricula to the 
auriculo- ventricular orifice. They are named from their re- 
semblance to the teeth of a comb. They are crossed by other 
fasciculi, which cause a reticulated appearance. This reticu- 
lated arrangement is observed especially in the auricular 
appendix. The inner and outer membranes are in contact 
with each other between the muscular fasciculi in some por- 
tions of the auricle. In examining the structure of the walls 
of the auricle it will be seen that they are not adapted to 
exert much force in expelling the blood from the auricle into 
the ventricle. 

The interior of the Eight Yentkicle should now be ex- 
amined. For this purpose make two incisions from its apex 
to its base, along the ventricular septum, and raise the whole 
of its right and anterior wall without detaching it at the base. 
To facilitate the study of the parts around the auriculo- 
ventricular orifice, this flap may be divided through its 
centre. 

The following parts will be found in the dissection of this 
cavity : — 

The columnoe carneoe are muscular projections on the inner 
surface of the ventricle. They present three different kinds 
of arrangement. The first kind are adherent to the walls 
throughout their whole extent. The second are attached to 
the walls at their extremities, while the middle part of each 
is surrounded by the lining membrane of the ventricle. They 
cross each other in different directions, so as to form a reticu- 
lated appearance. The third set, or musculi papillares^ are 



THE HEART. 305 

few in number. They are attached, by one extremity, to the 
walls of the ventricle, and by the other to the chordae tendi- 
neas; they have been called the muscles of the heart. The 
fleshy columns give to the internal surface of the ventricle 
an irregular areolar appearance, and increase the extent of 
the lining membrane. 

The chordod tendinece are small tendinous cords which ex- 
tend from the third set of the columnae carnese to the tricuspid 
valve, Fig. 132, c; some of them, however, proceed directly 
from the parietes of the ventricle to the valve. These 
tendinous chords enter largely into the formation of the valve, 
which they traverse in different directions ; some of them are 
inserted into the fibrous zone which surrounds the margin of 
the auriculo-ventricular orifice. They enable the fleshy 
columns to which they are attached to separate, in the first 
place, the tricu.spid valve from the parietes of the ventricle, 
and thus allow the blood to get beneath it, and when the 
valve is forced upwards to close the opening they act as stays 
by preventing it from being carried into the auricle. 

The tricuspid valve ^ Fig. 132, c, consists of an annular fold 
reflected from the margin of the auriculo-ventricular orifice 
into the ventricle. Its free border is usually divided into 
three segments, but sometimes into four, or even more. It 
contains, besides the chordae tendineas, some fibrous tissue 
which projects into it from the margin of the opening into 
the auricle. Small fleshy masses are sometimes observed 
attached to its free border. The largest of the three seg- 
ments is placed between the openings into the auricle and 
pulmonary artery. This segment may, perhaps, prevent the 
blood from passing into the pulmonary artery during the 
filling of the ventricle. The tricuspid valve closes the open- 
ing between the auricle and ventricle, when the latter con- 
tracts to force the blood into the pulmonary artery. 

The auriculo-ventricular orifice is situated at the right and 
posterior part of the base of the ventricle. It is of an ellip- 
tical form, and is surrounded by a fibrous band or zone, to 
which the tricuspid valve and muscular fibres in the parietes 
of the auricle and ventricle are attached. Its antero-posterior 
diameter is larger than the transverse. 

The conus arteriosus, or infi(udihulum, Fig. 132, a, is a pro- 
jection of the ventricle upwards to join the puhuouary artery. 
It is situated at the anterior and left i^ortion of the base. The 



306 DISSECTION OF THE THORAX. 

inner surface of the infundibnlum is smootTi, wliicTi facilitates 
the passage of the blood from the ventricle into the pul- 
monary artery. The term locus ijJanus has been applied to 
this surface. 

The mouth of the pulmonary artery is situated at the upper 
part of the infundibnlum, and about three-fourths of an inch 
from the opening into the auricle, from which it is sepa- 
rated by a muscular elevation. It is about three-fourths of 
an inch in diameter, is round, and surrounded by a fibrous 
zone to which are attached muscular fibres of the walls of 
the ventricle, the middle coat of the artery, and the semilunar 
valves. 

To examine the semilunar valves and the sinuses of Yal- 
salva, the pulmonary artery must be slit up for an inch or 
more from its commencement. 

The semilunar^ or sigmoid valves^ at the mouth of the pul- 
monary artery, are similar in appearance and structure to 
those at the mouth of the aorta, Fig 134 (i, 2, 3). They are 
three in number. They consist of folds of the lining mem- 
brane of the ventricle and artery, inclosing a fibrous tissue 
similar to the middle coat of the latter. When they are de- 
pressed and made tense, each presents a smooth convex sur- 
face towards the ventricle, and a concave surface towards the 
artery. In the centre of the free border of each valve is a 
small nodule or sesamoid body, named corptis Arantii Fig. 134, 
c. When the valves are depressed and these small bodies are 
brought in apposition in the centre, a perfect closure of the 
mouth of the artery is secured. The semilunar valves, 
although thin and apparently very delicate, are capable of 
resisting a great deal of force. They offer no resistance to 
the passage of the blood from the ventricle into the artery, 
but effectually prevent its return from the latter into the 
former. 

The sinuses of Valsalva, Fig. 134, 5, t, t, consist of three small 
pouches, situated at the commencement of the pulmonary 
artery, and, also, as will be seen, at the commencement of the 
aorta. They are formed, by dilatations, in. the coats of the 
artery, between which and the concave surfaces of the valves 
they are placed. They secure the closure of the valves by 
allowing the blood to get between them and the walls of the 
artery. They are more distinct in old than in young per- 
sons. 



THE HEART. 



307 



The student should now proceed to the dissection of the 
left side of the heart, beginning with the auricle. To reach 
this cavity, the apex of the heart must be drawn forwards 
and upwards. Make a vertical incision between the mouths 
of the pulmonary veins on the right and left side, and another 
from this into the auricula. 

The Left Auricle is of a cuboidal form, especially that 
portion which corresponds to the sinus of the right auricle. 
It is not quite so large as the right, but has thicker and 
stronger parietes. The ap2:)endix auriculce, Fig. 133, d, is 
longer and more curved than that of the right auricle, but is 
not so large. Its junction with the sinus, or larger portion, 
is marked by a constricted orifice. The muscuU pectinati 
are found only in this part of the auricle, and are less nume- 
rous than in the right appendix. 



Fig. 133. 



Heart seen from behind, and 

HAVING THE LeFT AuRICLE AND 

Ventricle opened. Parts in Left 
Auricle. — a. Smootli wall of auri- 
cular septum, c, e, c. Openings of 
the four pulmonary veins, d. Left 
auricular appendage, e. Slight de- 
pression in the septum, corresponding 
to the fossa ovalis on the right side. 
A probe is seen which passes down 
into the ventricle through theauricu- 
lo-ventricular orifice. Parts in Left 
Ventricle. — i. Posterior segment of 
the mitral valve, behind which is the 
probe passed from the left auricle. 
n, n. The two groups of qiusguH pa- 
pillares. o. Section of the thick 
walls of this ventricle, Avhich may be 
compared with that of the walls of 
the right ventricle, r. Entrance of 
inferior cava into right auricle. 




The inner surface of the sinus is, for the most part, smooth. 
The septtim aimcularum, Fig. 133, a, presents no depression, 
or only a very slight one, corresponding to the fossa ovalis. 
Wheiran opening does exist between the auricles, a small 
valvular fold may be observed. The mouths of the pulnw- 
nary veins, Fig. 133, c;, c, c, will be seen, two on the right, 
and two on tlic left side. Sometimes tlio veins on the same 



308 DISSECTION OF THE THORAX. 

side open into tlie auricle by a single orifice. The mouths of 
the pulmonary veins have no valves. The auriculo- ventricu- 
lar orifice is situated at the lower and anterior part of the 
auricle. 

To expose the cavity of the left yentricle, make two in- 
cisions from the apex to the base, along the septum ventricu- 
lorum. In doing this, care should be taken not to injure the 
parts within the cavity. To obtain a good view of the 
mitral valves, the flap thus raised may be divided into two 
by making an incision through its centre. 

The general appearance of the interior of the left ventricle 
is similar to that of the right, and it contains nearly the same 
number of things to be examined. 

The columncE carneoe- are not so numerous as in the right, 
but present the same general arrangement. They are divided 
into three sets, which are distinguished from each other in 
the same manner as in the right. Near the mouth of the 
aorta they are absent, and, consequently, the surface is here 
smooth. Those which have the chordge tendineae attached to 
them are larger and stronger than the corresponding ones in 
the right ventricle. 

The cliordce, tendinece are larger, but fewer in number. 
They connect the mitral valve to the fleshy columns, and at 
the same time enter into the structure of this valve, and con- 
tribute much to its strength. 

The mitral valve is situated at the auriculo -ventricular 
opening. Its structure is similar to that of the tricuspid 
valve. Its free margin is usually divided into only two seg- 
ments. The term mitral has been applied to this valve from 
its fancied resemblance to a bishop's mitre. The right ante- 
rior segment is the largest. From its position at the base of 
the ventricle, it is capable of closing the opening into the 
aorta, or of assisting in closing the opening into the auricle. 
The left posterior segment is smaller, and, also, has less 
mobility. 

The auriculo-ventricular orifice is smaller than the right. 
Its transverse diameter is greater than its antero-posterior. 
It is surrounded by a fibrous zone, which is blended in front 
and to the right side with the fibrous zone which surrounds 
the aortic opening. When it is viewed from the ventricle, it 
appears more like a fissure than an oval opening ; this results 



THE HEAET. 



309 



from the mitral valve having only two segments. The fibrous 
band which surrounds this opening furnishes an attachment 
for the muscular walls of the auricle and ventricle, and for 
the mitral valve. 

The aortic opening is round, and a little smaller than the 
mouth of the pulmonary artery. It is situated at the right 
anterior part of the base of the ventricle. There is here 
no infundibular prolongation upwards to join the aorta, as 
there is in the right ventricle to join the pulmonary artery, 
hence the mouth of the aorta is nearly on a level with the 
opening into the auricle. It is surrounded by a fibrous ring^ 
which forms a medium of attachment for the middle coat of 
the aorta, the semilunar valves, and the muscular parietes of 
the ventricle. This ring, it will be observed, is on one side, 
common to the aortic and auricular orifices, and forms the 
only septum between them. 

Fig. 184. 

Part of the Left Ventricle, 

AND commencement OF THE AoRTA 
LAID OPEN TO SHOW THE SiGMOID 

Valves. — a. Portion of the aorta. 
V. Muscular wall of the left ventricle. 
1, 2, 3. Semilunar or sigmoid valves. 
c, Corpus Arantii in one of them. 
e. Thin lunated marginal portion 
or lunula, s, t, t. Sinuses of Val- 
salva, t, t. Mouths of the two coro- 
nary arteries of the heart. m. 
Anterior segment of the mitral 
valve, the fibrous structure of which 
is continuous above with the aortic 
tendinous zone, opposite the attach- 
ed margin of the sigmoid valve, 
marked 1. Opposite the valves 2 
and 3, the tendinous zone receives 
below the muscular substance of the 
ventricle v. h. Larger chordae ten- 
dinag. o, o. Musculi papillares. 

The semilimar or Sigmoid valves, and the siiiuses of VaJsalva^ 
Fig. 134, have the same arrangement at the mouth of the 
aorta, as at the mouth of the pulmonary artery. The valves 
are thicker and stronger, while the sinuses are somewhat 
larger and more distinct. The corpora Arantii in these valves 
are particuL^rly well marked. In the sinuses, behind the 
left and antei'ior valves, will be found the orifi-cs of the 
coronary arteries. 




310 DISSECTION OF THE THOEAX. 

The cavities of the heart are lined by a serous membrane 
which is continuous with the lining membrane of all the 
vessels which communicate with these cavities. The different 
valves of the heart are formed, as has been seen, principally, 
by duplicatures of this membrane. It is not of equal thick- 
ness ■ throughout its whole extent. It is called the endo- 
cardium. 

By contrasting the form of the ventricles, and the thick- 
ness of their walls, they will be found to be quite different. 
The right ventricle has a pyramidal form, with three well- 
marked sides ; the inferior is^ flat, the anterior concave, and 
the left posterior, which corresponds to the septum ventricu- 
lorum, is convex. The left ventricle has a conical shape, and 
consequently presents no particular surface. The hase of 
each ventricle slopes from before backwards, and from above 
downwards, making the anterior surface longer than the 
posterior. It should be observed that the left ventricle is 
partly received into the right. There is probably little or 
no difference in the size of the two ventricles, although the 
capacity of the left seems to be much less than that of the 
right in the dead subject. This is owing to the flaccid con- 
dition of the walls of the right, while those of the left are 
firm and contracted. Each ventricle will contain about three 
ounces of blood. 

The walls of the left ventricle are about three times as 
thick as those of the right. The thickness, however, varies 
in each at different points. In the right the thickness is the 
greatest at the base, while in the left it is greater in the 
middle than at the base or apex. The thickness of the sep- 
tum ventriculorum is about the same as that of the walls of 
the left ventricle, of which it seems rather to be a part, than 
of the right. The relative thickness of the walls of the 
ventricles corresponds to the force which each is required to 
exert in propelling the blood through the vessels. 

The relative position of the four great orifices at the base 
of . the heart should be noticed. To do this the auricles 
should be detached just above the an riculo- ventricular open- 
ings, and the pulmonary artery and aorta just above their 
mouths. The openings between the auricles and ventricles. 
Fig. 135 (4, 7), will be found to occupy the posterior part and 



THE HEAET. 



811 



sides of tlie base of the ventricles, wMle tlie moutli of the 
aorta, Fig. 135 (i o), is situated between and in front of them; 
the orifice of the pulmonary artery, Fig. 135 (i i), is situated 



Fig. 135. 




a tertical view of the auricuiio- 
Ventrictjlar and Arterial Valves, 

AS GIVEN BY A SECTION OP THE HeART 

AT THE Ostium Venostjm and of the 
Arteries at their Valves. — 1. De- 
pression in the left auricle at the left 
ostium venosuin. 2. Depression in the 
right auricle at the right ostium veno- 
sum. 3, 3. Section of the parietes of the 
left auricle. 4. Superior or auricular face 
of the two folds of the mitral valve. 5. 
Section of the greater coronary vein. 
6, 6. Section of the parietes at the base 
of the right auricle. 7. Auricular face 
of the three folds of the tricuspid valve. 
8. The orifice of the greater coronary 
vein. 9. Septum of the auricles. 10, 
A section of the aorta to show its sig- 
moid valves. 11. The pulmonary artery 
with its valves. 



in front, and a little above and to the left of that of the 
aorta. 

These orifices are surrounded hj fibrous zones which, taken 
together, may be regarded as forming the framework of the 
heart. While they give to each orifice its particular shape, 
they furnish a fixed attachment for a portion of the muscular 
parietes of the heart, for the valves, and for the fibrous coats 
of the aorta and pulmonary artery. The space between the 
fibrous rings of the auriculo-ventricular openings and the 
mouth of the aorta, is filled Avith a dense fibrous substance, 
which adds greatly to the solidity of this part of the heart. 
A bone is frequently found in this space, in the hearts of 
some of the lower animals. 

The heart may be regarded as a hollow muscle, divided 
into two compartments. These are subdivided into the 
auricular and ventricular, which have no muscular fibres in 
common. The muscular parietes of the auricles contain 
fibres which are common to both, and others which belong- 
to each exclusively. The same is true of the ventricles. The 
muscular structure of the heart seems to dilYcr from that of 
every other organ in the body. It partakes, more or less, of 



312 DISSECTION OF THE THOKAX. 

tlie cTiaracter of both, the striated and non-striated muscles, 
and yet is different from either of them. It is exceedingly- 
dense and compact, with scarcely any areolar tissue inter- 
vening between its fibres or fasciculi. The fibres are vari- 
ously arranged. Some of them have a parallel direction, 
while others interlace and intermix with each other. In 
function, the heart is closely allied to the non-striated or in- 
voluntary muscles. 

The MuscuLAK Fibres of the Auricles, Fig. 136, are 
divided into the proper and common. The common have a 
transverse direction, and are, for the most part, superficial. 
They are attached to and extend between the fibrous zones 
of the auriculo-ventricular orifices. They form a very distinct 
layer on the anterior walls behind the aorta. Some fibres 
pass into the septum auriculorum. The projoer fibres have 
not the same arrangement in the two auricles. In the left^ 
they are expanded over the parietes so as to form a smooth 
even surface. They consist of fasciculi, which have either a 
circular or oblique direction, and are attached to the fibrous 
ring of the opening into the ventricle. Fasciculi spread 
out between the orifices of the right and left pulmonary 
veins, and also pass between and around those of the same 
side. Some fibres surround the auriculo-ventricular open- 
ing; others pass into the septum auriculorum, while others 
still mix with the common or superficial fibres. In the 
auricula, they form a network. In the right auricle, the 
fibres are arranged more distinctly in fasciculi, leaving between 
them interspaces in which the endocardium and pericardium 
are separated merely by areolar tissue ; they are also limited 
to a portion of the walls. The direction of the fibres varies, 
being either oblique or circular. They are attached to the 
fibrous zone of the auriculo-ventricular opening. In the 
auricula, they form a reticulated arrangement. 

The Muscular Fibres of the Ventricles, Fig. 136, like 
tbose of the auricles, are divided into the common and proper. 
The common fibres consist of two portions, the superficial, 
and the deep-seated or the reflected. The superficial fibres 
are situated on the outside of the proper, and become the deep- 
seated^ or refiected fibres, after they have penetrated the cavities 
of the ventricles at their apices. If they be traced, they will 



THE HEART. 



313 



Fig. 136. 




be found to arise from the auriculo- 
ventriciilar zones, and to pass down- 
wards, those in front from right to 
left, and those behind from left to 
right, to the apex of the heart. As 
they enter the ventricles, those from 
behind twist round those from be- 
fore, so as to form a stellated ap- 
pearance. Having entered the 
cavities of the ventricles, they pass 
upwards on the side opposite to 
the one upon which thej descended; 
so that the fibres which assist in 
forming the anterior walls as they 
descend on the outside, will assist 
in forming the posterior walls as 
they ascend on the inside. Some 
of them terminate by being inserted 
into the fibrous zones, and others 
in the columnse carnese. As many 
of the superficial fibres penetrate 
the ventricles before reaching the 
apex, loops of different lengths ^are 
formed one within another, thus 
increasing the thickness of the 
ventricular parietes from the apex 
towards the base. 

The proper fibres of the ventri- 
cles form two hollow truncated 

cones, which are covered on the outside by the superficial 
portion of the common fibres, and on the inside by the re- 
flected portion. There is one cone for each ventricle. Their 
bases are connected to the fibrous zones around the auriculo- 
ventricular openings. They are composed of circular, oblique, 
and spiral fibres. 

To unravel the muscular structure of the heart, the stu- 
dent should begin with that of a bullock. This should be 
prepared by boiling and maceration, until the fibres can be 
loosened up, and separated from each other. It will require 
much time and patience to trace out the different fibres and 
their connections. 
27 



A Posterior View of the Ex- 
ternal Muscular Layer of 
THE Heart after the removal 
OF its Serous Coat, &c. — 1. 
Right auricle. 2. Descending 
vena cava. 3. Right posterior 
pulmonary vein. 4. Muscular 
fibres of the left auricle. 5. Left 
posterior pulmonary vein. 6, 7. 
The arrangement of the muscular 
fibres at the end of the left auri- 
cle. 8. Orifice of the great coro- 
nary vein. 9. Band of fibres be- 
tween the two venae cavae. 10. 
The orifice of the ascending vena 
cava J the Eustachian valve is at 
the end of the line. 11, 12. Mus- 
cular fibres at the base of tho 
auricle. 13, 13, 14. Muscular 
fibres in tho ventricles. 



814 DISSECTION OF THE THORAX. 

The vessels of the heart consist of a right and left coronary 
artery, and a coronary vein. 

The Eight Coronary Artery, Fig. 130 (i i), arises from 
the aorta above the anterior semilunar valve. At first, it is 
concealed by the conns arteriosus, between which and the 
right auricle, it passes to enter the auriculo-ventricular groove ; 
it winds round in this groove to the posterior part of the heart, 
where it divides into two branches, one to go along the pos- 
terior vertical groove to the apex of the heart, and the other 
to continue in the auriculo-ventricular groove, until it a:fias- 
tomoses with the left coronary artery. It gives off quite a 
large branch, which ramifies over the anterior and right por- 
tion of the right ventricle. 

The Left Coronary Artery, Fig. 131 (lo, n), arises 
near the root of the aorta, above the left semilunar valve. It 
passes between the conus arteriosus and the left auricle, 
soon divides into two branches, the largest of which enters 
the anterior vertical groove, and goes to the apex of the 
heart ; the other and smaller branch enters the auriculo-ven- 
tricular groove, and terminates by anastomosing with the 
corresponding branch of the right coronary. The coronary 
arteries anastomose freely with each other, not only at the 
apex and in the horizontal sulcus, but in different parts of 
the parietes of the heart. They vary in number and in the 
manner of their distribution. 

The Coronary Yein, Fig. 131 (9), commences at the apex 
of the heart, and ascends along the anterior vertical groove 
to the sulcus between the left auricle and ventricle, in which 
it continues to the posterior part of the heart, where it opens 
into the right auricle. In its ascending course, it receives 
branches from the anterior parietes of the ventricles ; as it 
winds round to the back of the heart, it increases very much 
in size, as it receives branches from the posterior parietes of 
the ventricles, and from the left auricle ; one of these branches 
occupies the posterior vertical groove, and is called the mid- 
dle coronary or cardiac vein. Besides the coronary vein and 
its branches, there are several small anterior cardiac veins, 
which open into the lower part of the right auricle. The 
coronary veins have no valves. 

The nerves which supply the heart consist of two plexuses, 
the anterior and ijosterior coronary. These are derived from 



THE MEDIASTINUM. 315 

the superficial and deep cardiac plexuses, which will be de- 
scribed in coDnection with the contents of the superior medi- 
astinum. They accompany the coronary arteries only for a 
short distance, when they leave them to divide into branches 
to be distributed to the parietes of the heart. They can be 
seen for some distance in their course towards the apex of the 
heart, beneath the serou.s membrane ; they are more distinct 
in a heart which has been macerated for a few days in alcohol. 

The student should now proceed to examine the contents of 
the POSTERIOR MEDIASTINUM. They are readily exposed by 
dissecting the pericardium from the diaphragm, and detaching 
the pleura on each side as it is reflected from the pericardium 
to the vertebrae and ribs. They consist of the oesophagus, 
the aorta, the azygos vein, the thoracic duct, and the pneumo- 
gastric nerves. The great splanchnic nerves enter this space 
just before they pass through the diaphragm. These parts 
should be preserved, to be referred to again in the examina- 
tion of the contents of the superior mediastinu.m, in which 
they are also found. 

The oesophagus occupies the anterior part of this space, 
immediately behind the pericardium. It has the left pneumo- 
gastric nerve adhering to it in front, and the right behind. It 
perforates the diaphragm opposite the ninth dorsal vertebra. 

The aorta^ in passing through this region, has a direction 
somewhat oblique from the left to the right. It is situated 
on the left side, and is partly covered by the left pleura. The 
branches which it gives off, in this part of its course, will be 
noticed at another time. It enters the abdomen between 
the crura of the diaphragm, where it rests on the eleventh 
and twelfth dorsal vertebrae. The vena azygos is placed on the 
right side ; it is partly covered by the right pleura. It enters 
this space from the abdomen through the aortic opening in 
the diaphragm. The thoracic duct lies between the azygos 
vein and the aorta, and behind the oesophagus. It requires 
some care to be able to distinguish it from the areolar tissue 
around it. It passes through the diaphragm with the aorta 
and vena azygos. The splanchnic nerves will be seen on the 
sides of the bodies of the vertebra?, gradually getting more 
in front of them to perforate the crura of the diaphragm. 

The contents of the Superior Mediastinum are numerous, 
and their arrangement somewhat complex. The student, in 
his examination of them, should pursue a systematic course, 



316 DISSECTION OF THE THOKAX. 

SO that he may learn the position and relations of each part. 
His greatest difficulty will be to dissect out some parts, and 
preserve them, so as to see and learn their relations without 
destroying other parts. This difficulty may, however, to a 
considerable extent, be overcome, if he will carefully read a 
description of what he is to look for before he commences 
his dissection. 

The following are the things to be found and examined in 
this dissection : The remains of the thymus gland, the vena 
innominata, the vena transversa, the vena cava descendens, 
the vena azygos, and several smaller veins, as the superior 
intercostal, the thyroid, the mediastinal, and the bronchial ; 
the aorta, the arteria innominata, the left common carotid, 
the left subclavian, the bronchial, and the oesophageal arteries : 
the pulmonary arteries and veins; the pneumogastric, the 
phrenic, and the sympathetic nerves ; the trachea ; the oeso- 
phagus ; the thoracic duct ; and the bronchial glands. 

The Thymus GtLANd in the adult subject, exists only in the 
form of a small quantity of cellulo-adipose substance. In 
the old subject, very frequently, no trace of it is to be found. 
In the latter part of foetal life, and for some time after birth, 
it exists as quite a large body, reaching from a short distance 
below the thyroid gland nearly down to the diaphragm. It 
may become so large, especially in scrofulous children, as to 
cause death by pressing upon the trachea, or the oesophagus 
and other parts which are situated beneath it. 

The phrenic nerves should be sought and traced in the early 
stage of the dissection ; this can be done without disturbing 
other parts. The right nerve enters the thorax between the 
subclavian vein and artery. As it descends it has on the outer 
side the vena innominata covered by the pleura, and on the 
inner side the vena cava descendens and the pericardium. It 
passes in front of the root of the lung. The left nerve de- 
scends at first between the pleura and the left carotid artery ; 
it then passes in front of the left portion of the arch of the 
aorta and the root of the lung to get between the pleura and 
the pericardium. These nerves are accompanied by small 
branches of the internal mammary arteries. 

The following veins may next be examined : — 

The Yena Innominata, Fig. 139 (i i), is formed hj the 
junction of the right subclavian and internal jugular, be- 
hind the sternal end of the right clavicle ; it passes down- 



CONTENTS OF MEDIASTINUM. 317 

wards about an inch, and a half, where it unites with the vena 
transversa to form the descending cava. 

The Yena Teansveesa, Fig. 139 (i 4), commences behind 
the sternal extremity of the left clavicle, where it is formed 
by the union of the left subclavian and internal jugular veins; 
from this point it descends obliquely to the right, about three 
inches, to join the descending cava. It is usually somewhat 
larger than the innominata. It lies above the arch of the 
aorta, and rests on the great arteries which arise from it. 
It is separated from the sternum by the remains of the thy- 
mus gland and by areolar tissue. 

There are several small veins which open into the venae 
innominata and transversa. The former receives the right 
vertebral^ and generally the right internal mammary and inferior 
thyroid; the latter has opening into it the corresponding veins 
on the left side, and also the thymic^ the 'pericardiac^ the supe- 
rior phrenic^ and the superior intercostal. These veins vary 
very much in their termination in different subjects. 

The Yena Cava Descendens, Fig. 139 (10), commences 
opposite the first intercostal space, descends to near the car- 
tilage of the third rib, where it perforates the fibrous lamina 
of the pericardium, and thence continues down to the right 
auricle. It has the pleura and phrenic nerve on the right 
side, the aorta on the left, and the trachea, the right pulmo- 
nary artery, and superior pulmonary vein behind. Just be- 
fore it enters the pericardium it receives the vena azygos^ 
which passes up behind the root of the lung, and then bends 
forwards to terminate in the cava. 

The bronchial veins terminate, the right in the vena azygos, 
and the left in the superior intercostal. To obtain a good 
view of the vena azygos, the heart and lungs should be re- 
moved from the thorax. 

The Pneumogasteic N'eeves should now be examined. 
The right nerve enters the thorax between the subclavian vein 
and artery, crossing the latter nearly at a right angle ; it then 
descends behind the vena innominata and on the side of the tra- 
chea to reach the groove between the hitter and the a^sophagus, 
in which it continues until it gets behind the root of the rtght 
lung. The left nerve enters the thorax behind the vena trans- 
versa, and between the subclavian and connnon carotid arte- 

27* 



318 DISSECTION OF THE THORAX. 

ries ; it then descends between these arteries to the aorta, 
which it crosses over and then dips down behind the root of 
the left lung. Each nerve gives off a recurrent laryngeal 
branch ; the right just as it passes over the subclavian artery, 
and the left as it crosses the aorta. The left recurrent 
branch winds round behind the aorta, and ascends to the 
larynx in the groove between the trachea and the oeso- 
phagus; the rigJit passes round the subclavian artery and 
ascends to the larynx in the corresponding groove on the 
right side. The recurrent nerves give off cardiac, oesoj)ha- 
geal, tracheal, and pharyngeal branches. The left is longer 
than the right, and gives off more cardiac branches. 

Each pneumogastric nerve forms two pulmonary plexuses, 
one in front and one behind the root of the lung. The one 
in front, called the anterior pulmonary plexus, is formed by 
filaments which leave the nerve just above the root of the 
lung ; it also receives filaments from the phrenic and cardiac 
nerves. The one behind, named the posterior ptulmonary 
plexus, consists of a plexiform arrangement of the filaments 
of the nerve itself; it receives filaments from the anterior 
plexus, and from the cardiac nerves. The pulmonary plex- 
uses give off filaments which accompany the bronchial tubes, 
and ramify minutely in the lungs. The pneumogastric nerves, 
after forming the posterior pulmonary plexuses, join the oeso- 
phagus, which they accompany to the stomach. Filaments 
from each unite round this tube to form Xho, plexus gulce. 

It is somewhat difficult to dissect out the posterior pulmo- 
nary plexuses, as their filaments are intermixed with glands 
and areolar substance, There is an interchange of filaments 
between the two plexuses which establishes a direct sympa- 
thetic connection between the two lungs. The left plexus is 
considerably larger than the right. 

The Aorta commences at the anterior and inner part of 
the base of the left ventricle, opposite to the jimction of the 
cartilage of the fourth rib and sternum, on the left side. From 
this point it proceeds upwards, forwards, and to the right 
side as far as the junction of the cartilage of the second rib 
with the sternum ; it then turns to the left and goes back- 
wards to the body of the second dorsal vertebra, where it 
curves downwards and somewhat inwards on the side of the 
vertebrae, to enter the posterior mediastinum. 

This part of the aorta is divided into the ascending, trans- 



CONTENTS OF MEDIASTINUM. 



319 



verse, and descending portions, which together form what is 
denominated the arch of the aorta. At its commencement, 
the ascending portion, Fig. 137 (i), lies behind the infundibu- 
lar process of the right ventricle and the pulmonary artery, 



Fig. 137. 

The Large Vessels which 
proceed from the koot of 
THE Heart, with their Re- 
lations; THE Heart has 
BEEN removed. — 1. The as- 
cending aorta. 2. The arch. 
3. The thoracic portion of 
the descending aorta. 4. The 
arteria innominata, dividing 
into, 5, the right carotid, 
which again divides at 6, 
into the external and inter- 
nal carotid; and 7, the right 
subclavian artery. 8. Tho 
axillary artery; its extent is 
designated by a dotted line. 
9. The brachial artery. 10. 
The right pneumogastrie 
nerve running by the side of 
the common carotid, in front 
of the right subclavian artery, 
and behind the root of the 
right lung. 11. The left 
common carotid, having to its 
outer side the left pneumo- 
gastrie nerve, which crosses 
the arch of the aorta, and as 
it reaches its lower border is 
seen to give off the left re- 
current nerve. 12. The left 
subclavian artery becoming 
axillary and brachial in its 
course, like the artery of the 
opposite side. 13. The trunk 
of the pulmonary artery connected to the concavity of the arch of tho aorta by a 
fibrous cord, the remains of the ductus arteriosus. 14. The left pulmonary artery. 
15. Tho right pulmonary artery. 16. Tho trachea. 17. Tho right bronchus. 18. 
The left bronchus. 19, 19. The pulmonary veins. 17, 15, and 19, on the right 
side, and 14, 18, and 19, on the loft, constitute tho roots of tho corresponding lunV, 
and the relative position of these vessels is preserved. 20. Bronchial arteries. 21. 
21. Intercostal arteries; the branches from the front of tho aorta above and below 
the number 3 aro pericardiac and oesophageal branches. 

but as it ascends it gradually approaches the sternum, from 
which the upper part is separated only by the pericardium, 
the remains of the thymus gland, and areolar tissue. It has 
the right auricle and the descending cava on the right side 
of it ; the pulmonary artery, at first in front and then on the 
left side; and behind, the right pulmonary artery and veins. 




320 DISSECTION OF THE THOKAX. 

The principal part of it is contained in the pericardium, and 
invested by the serous lamina of that membrane. The trans- 
verse portion, sometimes called the arch, Fig. 137 (2), lies 
nearest to the sternum. The vena transversa lies imme- 
diately above it, resting on the arteria innominata and the 
left common carotid and subclavian arteries. The ductus 
arteriosus and the right pulmonary artery occupy its cardiac 
aspect, while the trachea is in contact with it behind. The 
descending portion. Fig. 137 (3), has in front of it the left 
phrenic and pneumogastric nerves, and the root of the left 
lung. On the left side, and behind, it is in relation with the 
pleura and the body of the third dorsal vertebra. 

The attention of the student should be directed especially 
to this great vessel, as it furnishes a key to the study of the 
relations of almost all the other parts found in the superior 
mediastinum. Besides, a knowledge of it is of the utmost 
importance, if we wish to understand the nature and the 
results of aneurisms, which are formed in it. 

The Arteria Innominata, Fig. 137 (4), arises from the 
arch of the aorta, near the median line, and extends obliquely 
upwards to a point behind the right sterno-clavicular articula- 
tion. It varies in length from an inch to an inch and a half. 
It is separated from the sternum by the vena transversa, the 
sternal mascles and areolar tissue ; on the right side, it is in 
relation with the vena innominata and the pleura ; behind, 
it rests, at first, on the trachea, and then gets to its right side ; 
on the left side, it is separated from the left common carotid 
artery by a triangular space, in which the trachea is seen. 
This artery divides into the right common carotid and subcla- 
vian. It sometimes gives off one or two small branches, 
especially the middle thyroid, or the artery of Neubauer. 

The Left Common Carotid Artery, Fig. 137 (1 1), arises 
from the arch of the aorta immediately to the left of the inno- 
minata. It passes obliquely upwards to the left, to reach the 
neck. The vena transversa and the sternal muscles lie in 
front of it ; the trachea and oesophagus are behind it ; the 
pleura partly covers it on the left side. 

The Left Subclavian Artery, Fig. 137 (1 2), arises from 
the aorta to the left and behind the left common carotid. Its 
direction is nearly vertical. It is covered on the left side by 



. THE TRACHEA. 821 

the pleura ; the pneumogastric and phrenic nerves, the vena 
innominata, and the sternal muscles are in front of it ; the 
trachea and oesophagus are on the inside of it. 

The arteries just described vary a good deal in their origin 
from the arch of the aorta. 

The Pulmonary Artery, Fig. 137 (i s), is from an inch and 
a half to two inches in length. It passes upwards, backwards, 
and somewhat to the left. At first, it is in front of the aorta, 
and then gets to its left side. Nearly the whole of it is covered 
by the serous layer of the pericardium. It divides into the 
right and left pulmonary arteries. At its bifurcation, the 
remains of the ductus arteriosus is found extending from it 
to a point on the arch of the aorta, nearly opposite to the 
origin of the left subclavian artery. 

The Eight Pulmonary Artery, Fig. 137 (i 5), is directed 
transversely to the root of the right lung. It is about an 
inch and a half in length. It passes behind the aorta and 
the vena cava descendens, and in front and a little below the 
right bronchus. In the root of the lung, it divides into three 
branches. The serous lamina of the pericardium is reflected 
upon a portion of this artery. 

The Left Pulmonary Artery, Fig. 137 (14), is quite 
short. It proceeds to the left lung in front, and a little above 
the left bronchus, and also in front of the descending portion 
of the aorta. It divides into two primitive branches. 

The Pulmonary Yeins, Fig. 137 (1 9,1 9), consist of four 
principal trunks, two for each lung. These are formed by 
branches, which originate in the walls of the air-cells of the 
lungs. One of the right veins is formed by branches proceed- 
ing from the lower lobe, while the other is formed by branches 
from the middle and superior lobes. 1}\\q former has a trans- 
verse, and the latter an oblique direction towards the left 
auricle. In the root of the lung on each side, the veins are 
situated anteriorly, the bronchus posteriorly, and the artery 
in the middle. From above dowuAvards, on the right side, 
the bronchus is situated above, the veins below, and the artery 
in the middle ; while, on the left side, the artery is placed 
above, and the bronchus in the middle. 

The Trachea, Fig. 138 (7), extends from the fifth cervical 
vertebra above to the third dorsal below ; it commences at 



322 DISSECTION OF THE THORAX. 

the inferior border of the cricoid cartilage, and terminates by 
its bifurcation into the two bronchi. It is about five inches 
in length, and is nearly equally divided in its cervical and 
thoracic portions. Its diameter is about ten lines in the male, 
and a little less in the female. Sometimes it increases in. 
diameter from above downwards. Its direction is downwards, 
backwards, and a little to the right side. In the thorax, it has 
the oesophagus behind, and one of the pneumogastric nerves 
on each side of it ; the left recurrent nerve and left common 
carotid artery are on the left and the upper part of the arteria 
innominata on the right side; the lower part of the last 
named artery and the arch of the aorta are in front of it. 

The bivnchi, Fig. 138 (s, 9), extend from the trachea into 
the roots of the lungs. The right forms nearly a right angle 
with the trachea ; it is about an inch and a quarter in length, 
and half an inch in diameter. The vena azygos winds around 
it to enter the descending cava. The left hronchus is longer, 
and has a more oblique direction downwards than the right, 
to reach the root of the left lung ; it also has a smaller caliber. 
The oesophagus and descending aorta pass behind it. The 
bronchi at the bifurcation of the trachea are connected to- 
gether by quite a strong ligament. The triangular space 
between them is filled with bronchial glands, which usually 
have a very dark appearance. Filaments from the anterior 
and posterior pulmonary plexuses accompany the bronchial 
tubes into the substance of the lungs. 

The trachea, together with the bronchi and lungs, may be 
removed from the thorax, for the purpose of examining their 
structure. But, before doing this, the bronchial arteries^ Fig. 
137 (20), should be noticed. They arise from the descending 
aorta, and vary in number ; there may be two, three, or four. 
Sometimes one arises from the internal mammary, or the 
superior intercostal. They join the bronchi, and accompany 
them in their subdivisions through the lungs, which they 
supply with arterial blood, for their nourishment. The 
bronchial veins convey the blood which is transmitted to the 
lungs by the bronchial arteries into the vena azygos and the 
superior intercostal vein. 

The trachea is composed of imperfect cartilaginous rings, 
of muscular and fibrous tissue, and of glands and mucous 
membrane. There are from sixteen to eighteen cartilaginous 



THE TRACHEA. 



323 



rings ; they form tlie framework of tlie tube, keeping it con- 
stantly open for the transmission of air to and from the Inngs. 
Each ring embraces about three-fourths of the circumference 

Fig. 138. 




The Lahynx, Trachea anb Bronchi, deprived of their Fibrous Covering; 
also THE Outline of the Lungs. — 1, 1. Outline of the upper lobes of the 
lungs. 2. Outline of the middle lobe of the right lung. 3, 3. Outline of the infe- 
rior lobes of both lungs. 4. Outline of the 9th dorsal vertebra, showing its relation 
to the lungs and the vertebral column. 5. Thyroid cartilage. 6. Cricoid cartilage. 
7. Trachea. 8. Right bronchus. 9. Left bronchus. 10. Crico-thyroid ligament. 
11, 12. Rings of the trachea. 13. First ring of the trachea. 14. Last ring of the 
trachea, which is corset-shaped. 15. 16. A complete bronchial cartilaginous ring. 
17. One which is bifurcated. 18. Double bifurcated bronchial rings. 19,19. Smaller 
bronchial rings. 20. Depressions for the course of the large bloodvessels. 

of the trachea, leaving one-fourth behind to be filled b}' mus- 
cular fibres. They are more distinct on the inner than on the 
outer surface. The first ring is usually broader than the 
others, while the last two are larger. Frequently, two or 
three of them coalesce in some part of their circumference. 



324 DISSECTION OF THE THORAX. 

They are strong, elastic, and not easily broken. The last one 
consists of two segments of smaller circles, united at their 
inner extremities. Each of these segments is the commence- 
ment of one of the bronchi. 

The fibrous tissue is the yellow elastic kind. It forms a com- 
plete tube, which is attached to the cricoid cartilage above, 
and is lost below in the bronchi. The cartilaginous rings are 
imbedded in it, and are more thickly covered by it on their 
external than on their internal surface ; hence the difference 
in the prominence of the rings on the two surfaces. On the 
inside of the muscular portion of the tube, the elastic tissue 
forms, apparently, longitu.dinal folds, which, however, result 
from the fibres of this tissue being arranged in fasciculi. The 
use of the elastic tissue in the trachea is very evident. It con- 
tributes greatly to its strength, and, by its elasticity, prevents 
displacement of the organs with which the trachea is connected 
above and below, when' the head is thrown backwards. The 
trachea may be stretched to the extent of an inch or more, 
and recover its natural length as soon as the force is removed. 

The muscular fijres are situated behind, being attached to 
the ends of the cartilaginous rings. They have a transverse 
direction, and belong to the non-striated or involuntary class 
of muscles. They approximate the ends of the cartilages, 
and thus diminish the size of the tube. They also form a 
flattening of the trachea behind where it rests upon the 
oesophagus, which may facilitate the passage of the food 
to the stomach. 

The mucous membrane of the trachea is continuous with that 
of the larynx above, and that of the bronchi below. It is 
thin and transparent, and adheres closely to the subjacent 
tissues. It is perforated by numerous small foramina, through 
which the secretion from the tracheal glands is poured out 
upon the inner surface of the trachea. 

The tracheal glands consist of numerous small glandular 
bodies, situated in the parietes of the trachea. Those found 
behind, in the membranous part, are the largest. They are 
placed outside of the muscular layer, between it and the 
fibrous layer. The others are contained in the fibrous tissue 
between the rings. 

The bronchi may be regarded as a continuation of the tra- 
chea in two divisions. They have the same elements, with 
the same arrangement in their structure. The left bronchus 



THE LUNGS. 325 

has eight or ten, and the right five or six cartilaginous 
rings. 

The Lungs (Fig. 139) have already been observed in situ in 
examining the pleurae. To obtain a good view of their form 
and external appearance, they should be inflated after their 
removal from the thorax. If they be not injured in their 
removal, they will retain the air a suffiLcient length of time 
to allow of a satisfactory inspection. Each lung presents 
three surfaces, a costal, a diaphragmatic, and a mediastinal. 

The costal surface is convex, and corresponds to the ribs 
and intercostal spaces, being in apposition with the pleura 
costalis. This surface presents two fissures in the right lung, 
which divides it into three lohes^ Fig. 139 (21, 22, 23). The 
principal one commences behind, just below the apex, 
and extends downwards and forwards to the base near its 
inner margin ; the other, and smaller one, extends from this 
forward and somewhat downwards to the anterior border of 
the lung. The first one is much deeper than the last ; it 
reaches entirely to the root of the lung. The left lung has 
but one fissure, which corresponds to the large one in the 
right; consequently, this lung has but two lohes^ Fig. 189 
(24, 25). The number of lobes, however, is subject to va- 
riation in both lungs. 

The diaphragmatic surface is concave, and sloping from 
before backwards and downwards, so that the vertical dia- 
meter of the lung is considerably greater behind than before. 
The concavity of the right is deeper than that of the left, 
on account of the liver pushing the diaphragm higher up 
on the right side. The margin of this surface presents quite 
a sharp edge, which projects in between the diaphragm and 
the costal parietes of the thorax. 

The mediastinal surface is in contact with the pleura medi- 
astinalis. This surface in each has a concavity for the re- 
ception of the heart ; the one in the left is the deepest, on 
account of the heart projecting more on the left than on the 
right side. The posterior border is round, and nearly straight 
from the apex to the base of the lung ; while the anterior is 
sharp, oblique, and notched; the left for the apex of the 
heart, and the right for the right auricle ; besides these 
notches, there is a small one on the right side for the de- 
scending cava, and another on the left for the subclavian 
28 



326 DISSECTION OF THE THORAX. 

artery. Tlie apex of eacli lung is round, and projects some 
distance above the first rib ; the right more than the left. 

The color of the lung varies at different periods of life. In 
the child it is a pale red, while in the adult it is of a grayish 
blue, interspersed with dark spots, which increase in number 
as age advances. The posterior part after death usually 
presents, from hypostatic congestion, quite a dark hue. Lines 
may be observed on the surface of the lung through the 
pleura, which indicate the septa between the lobules. 

The right lung is somewhat larger than the left. The di- 
mensions of the two lungs are not precisely the same ; the 
vertical diameter of the left lung is the greatest, while the 
base of the right is rather larger than that of the left. The 
lungs of the male are usually larger than those of the female. 
In proportion to their bulk the lungs are very light ; this is 
owing to the air which is never wholly expelled from the cells 
after it has once entered them. When cut into they have a 
spongy appearance, and when a portion is compressed be- 
tween the thumb and fingers the air can be felt escaping 
from the cells. The resiliency of the lung is well shown in 
the force with which it expels the air when it has been in- 
flated. This contractile power exists in the yellow fibrous 
tissue which enters into its structure. 

The lung contains in its structure all the elements which 
are found in its root. They consist of the ramifications of the 
pulmonary artery and veins^ the hroncliial arteries^ veins^ and the 
hronchi^ together with nerves and ahsorhent vessels^ and the 
jparenchyma which holds all the other parts in situ. If a 
bronchus be traced into the substance of the lung, it will be 
found to divide and subdivide until it ultimately terminates 
in the air-cells. The mode of division observed is dichoto- 
mous ; that is, the bronchus divides into two tubes, and each 
of these again divides into two others, and so on until the 
last division takes place. 

The structure of the bronchial ramifications, after the first 
two or three divisions, undergoes some modification. The 
cartilaginous segments^ instead of being arranged on one side 
of the tube as in the trachea, are distributed on all sides of 
it, with their extremities overlapping each other. This ar- 
rangement continues to the last division, the segments, how- 
ever, becoming more and more imperfect until they dis- 



THE LUNGS. 



327 



appear altogether. The onuscular fibres connect the ends of 
the cartilages together and form on their inner aspect a 

Fig. 139. 




Anatomy op the Heart and Lungs. — 1. The right ventricle ; the vessels to the 
left of the number are the middle coronary artery and veins ; and those to its 
right, the anterior coronary artery and veins. 2. The left ventricle. 3. The 
right auricle. 4. The left auricle. 5. The pulmonary artery. 6. The right 
pulmonary artery. 7. The left pulmonary artery. 8. The remains of the ductus 
arteriosus. 9. The arch of the aorta. 10. The descending vena cava. 11. The 
arteria innominata, and in front of it the vena innominata. 12. The right sub- 
clavian vein, and, behind it, its corresponding artery. 13. The right common ca- 
rotid artery and vein. 14. The vena transversa. 15. The left carotid artery 
and vein. 16. The left subclavian vein and artery. 17. The trachea. 18. The 
right bronchus. 19. The left bronchus. 20, 20. The pulmonary veins; 18,20, 
form the root of the right lung; and 7, 19, 20, the root of the left. 21. The supe- 
rior lobe of the right lung. 22. Its middle lobe. 23. Its inferior lobe. 24. Tho 
superior lobe of the left lung. 25. Its inferior lobe. 



complete mnscular tube. The mucous membrane and fihroits 
tissue are prolonged into the lobular tubes, with which the 
cells communicate directly. Tho cells are not lined by mu- 
cous membrane, but have a thin, delicate, fibrous lamina 
forming their walls, upon which the capillaries of the pul- 
monary vessels ramify. 

Each lobule is composed of a cluster of air-cells, which 
communicate with a tube common to them ; of })ulnionary 



328 



DISSECTION OF THE THORAX. 



and broncHal vessels, nerves, and absorbents, so that it may 
be regarded as representing the entire lung. 

The i^idmonary artery accompanies the bronchial ramifica- 
tions in all their subdivisions, and finally forms a capillary 
network by anastomosing freely with the radicals of the pul- 
monary veins in the parietes of the air-cells. The pulmo- 
nary veins, commencing in the walls of the cells, accompany 
the bronchial tubes to the root of the lung. The bronchial 
vessels, nerves, and absorbents are all found ramifying with the 
air-tubes in the substance of the lung. The nerves are. de- 
rived from the pneumogastric and sympathetic. The ab- 
sorbent vessels consist of two sets, the deep and the superficial; 
they terminate in the bronchial glands. 

The (Esophagus has been noticed in the neck, and also in 
the posterior mediastinum. It is a muscular tube, com- 
mencing at the lower orifice of the pharynx and extending 
to the stomach. It is the smallest section, in diameter, of the 
alimentary canal, being usually less than an inch. It is 
narrower above than below, except where it passes through 
the diaphragm. It is composed of three layers ; a mucous, 
cellular, and muscular. The mucous mem- 
brane is a continuation of that of the pha- 
rynx. It is thrown into longitudinal folds 
when the oesophagus is empty. The cellular 
layer is intermediate to the other two, and 
allows of a somewhat loose connection be- 
tween them. The muscular layer. Fig. 140 
(i, 1, 2, 2), consists of longitudinal and cir- 
cular fibres ; the latter are internal to the 
former. The longitudinal fibres arise in 
part from the posterior aspect of the cricoid 
cartilage, and terminate in the muscular 
parietes of the stomach. The circular fibres 
cease at the cardiac orifice of the stomach. 
They all belong to the involuntary class of 
muscles. 

In the superior mediastinum, the oesopha- 



Fig. 140. 




A View of a portion of the (Esophagus of an Adult, seen on its outer 
SIDE. — 1, 1. External or longitudinal muscular fibres. 2, 2. Internal or circular 
fibres, as shown after the removal of the longitudinal ones. 3, 3. The cut edges 
of the longitudinal fibres, from which a portion has been removed, so as to show 
the circular ones. 



THE THOEACIC DUCT. 829 

gus lies in front of the vertebral column, and behind the tra- 
chea, being inclined a little to the left side. Its relations to the 
aorta in passing through the thorax are changed. At first it 
passes beneath the arch, then to the right of the descending 
aorta, and finally it gets nearly in front of it. Its course is 
slightly flexuous. 

The course of the aorta has already been observed. It 
gives off, besides the branches previously described, the oeso- 
phageal and intercostal: The oesophageal branches, Fig. 137 (3), 
vary in number and origin. There may be three, four, or 
more of them. They divide, after reaching the oesophagus, 
into ascending and descending branches, which perforate the 
muscular coat and ramify beneath the mucous membrane. 

The intercostal arteries, Fig. 137 (21, 21), arising from the 
aorta, usually consist of nine or ten on each side ; the supe- 
rior intercostal spaces being supplied from the subclavian 
arteries. They arise from the posterior part of the aorta, 
and proceed laterally to enter the intercostal spaces. Those 
on the right side, especially the superior ones, are much 
longer and more oblique in the first part of their course than 
the corresponding ones on the left side. As the intercostals 
enter the intercostal spaces, they give off posterior branches 
which go back to supply the muscles in the spinal fossse, and 
also to send twigs into the spinal canal through the inter- 
vertebral foramina. After giving off the posterior branches, 
they pass forwards along the lower borders of the ribs, occu- 
pying the intercostal grooves. Each artery divides into two 
or more branches, some distance from the sternum, which 
anastomose with branches from the internal mammary. 
They are accompanied by the intercostal nerves in the inter- 
costal spaces, and also the veins of the same name. 

The Thoeacic Duct, Fig. 141 (12, 13, 14), was seen in the 
posterior mediastinum, and was also noticed in the dissection 
of the neck. It commences in the rece^^aculuin cJii/li, which 
is situated on the second lumbar vertebra, and between the 
right or long crus of the diaphragm and the aorta. It enters 
the posterior mediastinum through the aortic opening in the 
diaphragm, between the aorta and azygos vein, and ascends 
nearly in a straight direction as far as the third cervical 
vertebra, having tlie a^sophagus in front of it ; it now turns 
to the left beneath the aorta, and gets to the left side of the 

2S'- 



330 DISSECTION OF THE THOKAX. 

oesophagus and to the inner side of the subclavian artery, and 
passes up in this direction to the fifth cervical vertebra, 
where it curves forwards and outwards to join the subcla- 
vian vein at its junction with the internal jugular. 

In passing through the thorax, it not unfrequently divides 
into two or three trunks, which again unite into one trunk 
before its termination; sometimes it terminates in two or 
three divisions, which have separate openings into the sub- 
clavian vein. It is the common trunk of the lymphatics of 
the whole body, except the right hah" of the/ head and 
neck, and the right upper extremity. The lymphatics of 
these parts terminate in the right thoracic duct^ Fig. 141 (is), 
which opens into the right subclavian at its union with the 
internal jugular vein. 

The Yeka Azygos Major, Fig. 141 (i o), commences in 
the abdomen near the second lumbar vertebra, and on the 
right side. It is formed by the union of branches from 
several veins, as the superior lumbar, renal, and capsu- 
lar. Sometimes it communicates directly with the ascending 
cava. It passes through the aortic opening in the diaphragm, 
and ascends on the bodies of the vertebrae as. far as the fourth 
dorsal, where it curves forwards over the upper border of the 
root of the luno^ to enter the descendino- cava. It crosses over 
the intercostal arteries. It receives in the thorax the right 
intercostal veins, except the upper one or two, the vena azy- 
gos minor, the oesophageal, mediastinal and bronchial veins. 

The Yena Azygos Minor, Fig. 141 (i i), commences in 
the lumbar region, on the left side, in a similar manner to 
that of the azygos major on the right side. It passes 
through the left crus of the diaphragm, usually with the left 
great splanchnic nerve, and ascends on the left side of the 
vertebral column, as far as the sixth or seventh dorsal verte- 
bra, where it passes over to the right side to join the vena 
azygos major; it crosses beneath the aorta and thoracic duct. 
It receives the inferior six or seven left intercostal veins, 
also, the oesophageal, phrenic, and mediastinal veins. 

The upper five or six intercostal veins, except the first 
on the left side, unite to form a common trunk, which is some- 
times called the superior vena azygos ; it empties ^ into one of 
the other azygos veins. The left superior intercostal gene- 
rally joins the vena transversa. The intercostal veins receive 
branches through the intervertebral foramina from the 



SYMPATHETIC NERVE. 



331 



spinal canal, and also from the muscles in the spina 
fossse on the back. By means of the azjgos veins, a commu 
nication is established between the two venas cavae. Thes e 
veins are not supplied with valves, so that the blood ma y 
pass from one cava to the other in either direction. 



Fig. 141. 



The Sympathetic Nerve may 
be seen in the thorax on each side 
of the vertebral column without 
any dissection. It consists of twelve 
ganglia on each side, and branches 
proceeding from them. The ganglia 
are situated near the heads of the 
ribs, and are covered by the pleura 
and a thin fascia. The first, second, 
and twelfth, are larger than the 
intermediate ones. The first is 
connected to the third cervical 
ganglion by filaments, which pass 
round the subclavian artery ; some- 
times the two ganglia are joined to 
each other. The twelfth is joined 
by filaments to the first lumbar. 

The ganglia are also connected 
to each other by filaments. Their 
branches are external and internal. 
The external connect the ganglia 
with the intercostal nerves. They 
consist of two sets of fibres, deep 
and superficial. They resemble the 
spinal nerves in their appearance. 
The internal branches are distrib- 
uted in the mediastinal space, and 
in the abdomen. Those from the 
upper five or six ganglia pass in- 

A View of the Course and Termination op the Thoracic Duct. — 1. Arch of 
the aorta. 2. Thoracic aorta. 3. Abdominal aorta. 4. Arteria iiinominata. 5. 
Left carotid. 0. Left subchivian. 7. Superior cava. 8. The twovona^ innominatte. 
9. The internal juguhir and subchivian vein at each side. 10. The vena azygos. 
n. The terniination of the vena azj-gos minor in the vena azygos. 12. The rocep- 
tacuhim chyli : several lymphatic trunks are seen opening into it. L>. The thoracic 
duet dividing, opposite the middle dorsal vertebra>. into two branches, which soon 
reunite; the course of the duct behind the arch of the aorta and left subclavian 
artery is shown by a dotted line. 14. The duct nnildng its turn at the root of the 
neck and receiving several lyiuphatic trunks previous to terminating in the poste- 
rior angle of tho junction of the internal jugular and subclavian veins. 15, The 
termination of tho trunk of tho lymphatics of tho upper oxtromitj. 




332 



DISSECTION OF THE THORAX. 



wards along tlie intercostal arteries, and are lost principally 
on the aorta ; some filaments go to the bodies of the verte- 
brge, and to the pulmonary plexus of the same side. 

Fig. 142. 




A View of the Great 
Sympathetic Nerve. — l.The 
plexus on the carotid artery 
in tlie carotid foramen. 2. 
Sixth nerve (motor externus). 
3. First branch of the fifth 
or ophthalmic nerve. 4. A 
branch on the septum narium 
going to the incisive foramen. 

5. The recurrent branch, or 
Vidian nerve divided into the 
carotid and petrosal branches. 

6. Posterior palatine branches. 

7. The lingual nerve joined 
by the chorda tympani. 8. 
The portio dura of the seventh 
pair or the facial nerve. 9. 
The superior cervical gan- 
glion. 10. The middle cervical 
ganglion. H. The inferior 
cervical ganglion, 12. The 
roots of the great splanchnic 
nerve arising from the dorsal 
ganglia. 13. The lesser splan- 
chnic nerve. 14. The renal 
plexus. 15. The solar plexus. 
16. The mesenteric plexus. 17. 
The lumbar ganglia. 18. The 
sacral ganglia. 19. The vesi- 
cal plexus. 20. The rectal 
plexus. 21. The lumbar plex- 
us (cerebro-spinal), 22. The 
rectum. 23. The bladder. 
24. The pubis. 25. The crest 
of the ilium. 26. The kidney. 
27. The aorta. 28. The dia- 
phragm. 29. The heart. 30. 
The larynx. 31. The sub- 
maxillary gland. 32. The 
incisor teeth. 33. Nasal sep- 
tum. 34. Globe of the eye. 
35, 36. Cavity of the cra- 
nium. 



SYMPATHETIC NERVE. 833 

Branches from the sixth or seventh, and the eighth, ninth, 
and tenth ganglia on each side, pass downwards and forwards 
on the sides of the vertebras to the lower part of the pos- 
terior mediastinum, where they nnite into one cord called 
the great splanchnic nerve, Fig. 142 (12), which perforates the 
diaphragm to reach the semilunar ganglion, on the side of 
the coeliac artery. Sometimes it passes through the aortic 
opening. 

The lesser splanchnic nerve on each side. Fig. 142 (is), is 
formed by branches from the eleventh and twelfth ganglia ; 
it passes through the crus of the diaphragm, and joins the 
solar plexus. A third splanchnic nerve sometimes arises 
from the twelfth ganglion, enters the abdomen, and goes to 
the renal plexus. 

The cardiac nerves and ganglion cannot well be dissected in 
the thorax, until the student has acquired a knowledge of the 
contents of the superior mediastinum. For this purpose two 
subjects will be required ; one for the viscera, and another 
for the nerves. The frequent variation met with in the 
arrangement of the cardiac nerves renders the study of them 
more or less unsatisfactory. They are derived principally 
from three sources, the cervical ganglia, the pneumogastric, 
and the recurrent nerves. Those from the cervical ganglia 
are named the superior, middle, and inferior cardiac. These in 
their course are joined by filaments from the recurrent and 
pneumogastric. They all terminate in the cardiac plexuses, 
from which filaments proceed to form the coronary plexuses 
on the heart. 

The superior cardiac nerve on each side arises, usually, from 
the first cervical ganglion, passes down the neck behind the 
sheath of the carotid artery, and enters the thorax behind the 
subclavian; sometimes it crosses over the artery. In the 
thorax, it accompanies the arteria innominata on the right 
side to its origin, where it divides into two sets of filaments; 
one set passes in front of the aorta to reach the superficial 
cardiac plexus, while the other passes behind it to join the 
deep) or great cardiac plexus. In its course in the thorax, it is 
joined by filaments from the recurrent, and the middle and 
inferior cardiac nerves. 

The oniddle cardiac nerve arises from the middle cer\'ical 
ganglion, or it may arise from the cord of the sympathetic, 
descends behind the carotid, and enters the thorax either be- 



334 DISSECTION OF THE THORAX. 

hind or in front of tlie subclavian a,rtery. In tlie thorax, its 
course is similar to that of the superior cardiac. It also re- 
ceives filaments from the pnenmogastric and recurrent nerves. 
It is generally the largest of the three cardiac nerves. 

The inferior cardiac nerve arises from the third cervical 
ganglion, and passes down behind the arteria innominata and 
aorta, and terminates in the deep cardiac plexus. It receives 
branches from the pnenmogastric and recurrent. 

The cardiac ganglion is situated between the arch of 
the aorta and pulmonary artery, on the right side of the 
remains of the ductus arteriosus. It receives filaments from 
the superior cardiac nerves, and also from the pnenmogas- 
tric. These filaments form the superficial cardiac jplexus^ from 
which filaments, together with others derived from the deep 
cardiac plexu.s, proceed downwards to form a plexus which 
accompanies the right coronary artery on the heart. 

The deep cardiac plexus is formed by filaments from the 
superior cardiac nerves, more from the right than from the 
left, by the middle and inferior cardiac nerves, and filaments 
from the pnenmogastric and recurrent. It is situated above 
the pulmonary artery, and between the arch of the aorta and 
the trachea ; a portion of it is also situated between the right 
pulmonary artery and the bifurcation of the trachea. From 
this plexus some filaments pass in front of the pulmonary 
artery, to join others from the superficial plexus. The greater 
portion of them, however, pass down behind and between 
this artery and the aorta, to form a plexus, which accom- 
panies the left coronary artery. Some filaments from this 
plexus also join the pnenmogastric nerves, and with them go 
to the lungs. 



Dissection of the Ligaments of the Thorax. 

The true ribs are joined to the sternum directly by cartilages, 
while the false ribs are connected to it indirectly by their car- 
tilages joining those of the true ribs. The sternal extremities 
of the ribs are excavated, and the cartilages are received into 
them, while the sternal ends of the cartilages of the true ribs 
are rounded, and received into concavities on the borders of 
the sternum. Synovial membranes are found between these 
cartilages and the sternum, except the first. They are con- 



LIGAMENTS OF THE THOEAX. 



335 



nected to the sternum bj ligamentous fibres, Fig. 143 (5), 
whicli surround the articu.lations and spread out on tlie sur- 
faces of that bone. Thej add very much to the strength of 
the bone, which, indeed, is 



Fig. 143. 




covered on both sides by 
strong ligamentous bands. 

It will be convenient to 
examine, at this time, the 
ligaments which join the 
clavicles to the first ribs, to 
the sternum, and to each 
other. 

The clavicle, on each side, 
is connected to the first rib 
by a single ligament, named 
the COSTO-CLAVICULAK, or 

the RHOMBOID, Fig. 143 (3). 
It arises from the lower 
border of the cla^acle, close 
to the sternum, and is in- 
serted into the cartilage of 
the first rib. Its direction 
is inwards and forwards. 

The clavicle is joined to 
the sternum by ligamentous 

fibres, which wholly surround the joint. They are sometimes 
designated the anterior and posterior sterno-clavicular 
LIGAMENTS, Fig. 143 (i), but there is no distinct line of sepa- 
ration between them. They form a sort of capsular ligament. 

This joint is usually divided into two cavities by an inter- 
ARTICULAR FIBRO-CARTILAGE, Fig. 143 (4), and contains two 
distinct synovial sacs. The fibro-cartilage is attached to the 
clavicle above, to the sternum below, and to the sterno-cla- 
vicular ligaments, anteriorly and posteriorly. It adds con- 
siderably to the strength of the joint. 

The two clavicles are connected together by an intercla- 
vicular LIGAMENT, Fig. 143 (.2), which stretches across the 
sigmoid notch at the upper extremity of the sternuni, the 
depth of which is, by means of it, somewhat diminisliod. 

All the ribs are joined directly to the vertebra> behind. 
With the exception of the first aiul the two last, each rib 
articulates, by its head, with the bodies of two contiguous 



The Ligaments of the Sterno-Clavi- 

CULAR AND CoSTO-StERNAL ARTICULA- 
TIONS. — 1. The anterior sterno-clavicular 
ligament. 2. The interclavicular liga- 
ment. 3. The costo-clavicular, or rhom- 
boid ligament., is seen on both sides. 4. The 
interarticular fibro-cartilage, brought into 
view by the removal of the anterior and 
posterior ligaments. 5, The anterior costo- 
sternal ligaments of the first and second 
ribs. 



836 



DISSECTION OF THE THORAX, 



vertebrae and their intervertebral substance. The ribs are 
also joined, by their tubercles, to the transverse processes of 
the vertebra. 

The head of each rib is connected to two bodies of the 
vertebrae and the intervertebral substance, by an anteeior 

COSTO-VERTEBRAL, Or STELLATE LIGAMENT, Fig. 144 (2), and an 

INTEROSSEOUS LIGAMENT, Fig. 144 (4). The j^rs^ arises from 



Fig. 144. 




Fig. 145. 




The Anterior Ligaments of the Ver- 

TEBRiE, AND THE LiGAMENTS OF THE RiBS. 

— 1. The anterior common ligament. 2. 
The anterior costo-vertebral, or stellate 
ligament. ^ 3. The anterior costo-transverse 
ligament. 4. The interosseous ligament 
connecting the head of the rib to the 
intervertebral substance, and separating 
the two synovial membranes of this arti- 
culation. 



A Posterior View of a part 

OP the Thoracic Portion of the 
Vertebral Column, showing the 
Ligaments connecting the Ver- 
tebra with each other, and the 
Ribs with the Vertebra. — 1, 1. 
The supra-spinous ligament. 2, 2. 
The ligamentasubflava, connecting 
the laminas. 3. The anterior costo- 
transverse ligament. 4. The pos- 
terior costo-transverse ligaments. 



the head of the rib in front, and is inserted, by three fasciculi, 
into the bodies of the vertebrae and the intermediate substance. 
The second arises from the angle between the facets on the 
head of the rib, and is inserted into the intervertebral sub- 
stance. The first and the two last ribs have no interosseous 
ligaments, and, consequently, each one has but a single syno- 
vial sac, while each of the others have two. 

The ribs are connected to the transverse processes by three 
ligaments, viz : The anterior, or internal costo-transverse, the 
posterior, or external costo-transverse, and the middle costo- 
transverse, or interosseous ligament. A small synovial sac 



LIGAMENTS OF THE THOKAX. 337 

is found between the tubercles of the ribs and the transverse 
processes. 

The Internal Costo-Transveese Ligament, Fig. 145 
(s), arises from the inferior border of the transverse process, 
passes obliquely downwards, and is inserted into the neck 
of the rib immediately below. This ligament is absent in the 
articulation of the first rib. 

The External Costo-Transverse Ligament, Fig. 145 
(4), extends obliquely from the apex of the transverse process 
to the tubercle of the rib. 

The Middle Costo-Transverse, or Interosseous Liga- 
ment, passes from the transverse process directly to the pos- 
terior part of the cervix of the rib. Its fibres are usually 
intermixed with more or less adipose tissue, and cannot be 
distinctly seen without making a section of the rib. 



29 



PAET III. 

DISSECTION OF ABDOMEN AND LOWER EXTREMITIES. 



CHAPTER I. 

OF THE ABDOMEN. 

Sect. I. — Parietes of the Abdomen. 

To dissect tlie parietes of tlie abdomen, tlie subject must 
be laid on the back, and elevated sufficiently, by means of 
one or more blocks placed beneath it, to render the muscles 
tense. The amount of elevation required will depend very 
much on the fulness of the abdomen, and must be deter- 
mined by the dissector in each case. 

The extent of the integument to be incised in this dissec- 
tion is indicated by the outlines of the external oblique 
muscle. If the student should wish to study the superficial 
fascia and the cutaneous vessels and nerves, it is immaterial 
how he makes his incisions for the purpose of removing 
the skin, as his object will be merely to uncover the fascia 
so as not to injure the vessels and nerves which ramify in 
it. But if his object be to raise the fascia with the skin, 
the incisions should be made with reference to the dissection 
of the external oblique muscle. 

As the fibres of this muscle are directed from above 
downwards and forwards, the integument must be raised so 
as to admit of exposing the muscle by cutting in the direc- 
tion of its fibres. If this rule be disregarded, and the student 
attempts to expose the muscle by cutting across the fibres, 
his dissection will necessarily be rough and unsatisfiictory. 
Whether the skin be raised separately or with the fascia, it 
is often convenient to leave the inguinal region untouched 
for the purpose of making a special d.isscction of the parts 



340 OF THE ABDOMEN. 

concerned in inguinal hernia. In this case, the dissection of 
the skin and fascia may be carried down only to a line ex- 
tending transversely across from the anterior superior spinous 
process of the ilium to the linea alba. The student will find 
the parts in the inguinal region described in the first place 
simply as forming a portion of the abdominal parietes, and 
afterwards with special reference to hernia. If he can dissect 
the lower extremity but once during the session, he had better 
reserve the inguinal region for a special dissection. 

Make an incision from the xiphoid or ensiform cartilage 
down to the symphysis pubis along the linea alba ; and an- 
other corresponding to the origin of the external oblique 
mu.scle. The last incision will extend laterally from the first 
over the lower eight ribs, and about three or four inches 
above the inferior border of the most prominent part of the 
thorax. If the pectoralis major and serratus anticus muscles 
have been previously dissected, this incision will not be re- 
quired ; if they have not been, the incision should be made 
so as to expose those portions of them which are in relation 
with the external oblique. 

Instead of making an incision over the origin of the ex- 
ternal oblique, the student may make one, commencing just 
above the umbilicus, and extending obliquely upwards and 
outwards, in the direction of the fibres of the external oblique, 
and then raise the integument in two flaps, one to be reflected 
upwards, and the other downwards. The advantage of this 
mode of procedure is that the external oblique is much 
thicker and its fibres more distinct in the line of this incision 
than it is in the upper part, where its fibres are short and 
comparatively few in number, and its aponeurosis is thin and 
liable to be cut through, thus exposing the rectus abdominis 
muscle. 

When the student has once obtained a distinct view of the 
fibres or fasciculi of a muscle, in whatever part of it, he can 
have no difficulty in dissecting it as long as he is careful to 
follow its fibres. In order to do this, he must take sufiicient 
time to remove the fascia entirely from every fasciculus as he 
proceeds in the dissection. 

The SuPEEFiciAL Fascia of the abdomen is continuous 
above with the fascia of the thorax, and below with that of 
the pelvis and lower extremity. In the upper and lateral 



PAEIETES OF THE ABDOMEN. 841 

parts of the abdomen it is thin, and requires no special notice. 
Over the linea alba it is thicker and more compact. Around 
the umbilicus it is dense, and seems to be blended with the 
tendon underneath. At the lower part of the linea alba it 
usually contains fibrous fasciculi, which go down to the dorsum 
of the penis; they constitute the suspensory ligament of that 
organ. It is prolonged round the spermatic cord into the 
scrotum, where it joins the superficial perineal fascia, and 
forms separate pouches for the testicles. 

In the inguinal region it is divided into a deep and super- 
ficial layer. The former is much more dense and compact 
than the latter ; it is adherent to Poupart's ligament, and 
appears to be continuous with the fascia lata in the upper 
part of the thigh ; a short distance above Poupart's ligament 
it is blended with the tendon of the external oblique. This 
lamina has been called the/ascm of Scarpa. The outer layer 
of the superficial fascia is areolar, and usually contains adi- 
pose substance in this region ; hence, it is sometimes called 
the adipose layer ; the inner layer is more compact, and con- 
tains yellow elastic tissue, which assists the muscles in sup- 
porting the abdominal viscera. 

The Cutaneous Aeteeies of the abdomen are derived 
from the internal mammary, the intercostal, the lumbar, the 
femoral, and the external iliac. The only one of any import- 
ance to be studied is the arteria ad cutem abdominis. This 
arises from the femoral artery a short distance below Pou- 
part's ligament, and passes upwards in the superficial fascia 
nearly to the umbilicus. It varies in size, but is rarely absent. 

The Cutaneous Neeves consist of branches of the lower 
five or six. intercostals and the lumbar. There are two sets 
of the cutaneous branches of the intercostals, the lateral and 
the anterior. The former are given off in the intercostal 
spaces, perforate the muscles, and divide into anterior and 
posterior filaments; the latter are the terminal branches of 
the intercostals, which, after leaving the intercostal spaces, 
pass forwards to the sheath of the rectus abdominis, which, 
together with the muscle, they perforate to reach the integu- 
ment near the linea alba. I^lie remaining cutaneous nerves 
are derived from branches of the lumbar plexus, and are dis- 
tributed in the lower part of the abdomen. 

There ai-e five pairs of muscles in the anterior and lateral 

29^^ 



842 OF THE ABBOMEK. 

parietes of the abdomen. They are the external and internal 
oblique, the transverse, the recti, and the pyramidal. To 
render these muscles tense for dissection, besides using blocks, 
it may sometimes be found convenient to distend the bowels 
either by inflation or by injecting water into them. 

The Obliquus Exteenus, Fig. 146 (12, 13), lies next to 
the superficial fascia. It arises from the eight inferior ribs 
near their cartilages, by as many fleshy digitations. These 
digitations project in between five similar ones belonging to 
the serratus anticus, and three belonging to the latissimus 
dorsi. It requires some care in dissecting to make these 
digitations distinct. A slip extends from the upper part to 
the pectoralis major. The length and direction of the fibres 
vary in different parts of the muscle. In the upper part they 
are short and quite oblique, in the middle they are longer 
but less oblique, while they are nearly perpendicular in the 
posterior part. 

The uj^j^er and middle fibres terminate in a broad aponeu- 
rotic tendon, which is inserted into the ensiform cartilage, the 
linea alba, the pubic bone, and Poupart's ligament ; the 'pos- 
terior fibres are inserted tendinous and fleshy into the anterior 
two thirds of the crest of the ilium. The student should be 
careful to observe where the muscular fibres join the tendon, 
so that he may avoid cutting through it. 

Poupart's Ligament, Fig. 146 (14), is regarded by some 
as the lower border of the tendon of the external oblique 
folded back upon itself By others it is considered as consist- 
ing of fibres which arise from the anterior superior spinous 
process of the ilium, and extending across the crural region, 
are inserted into the spine and crest of the pubic bone. That 
portion of it which is inserted into the crest of the pubis is 
called Gimhernath ligament. 

The external oblique muscle is capable of acting in several 
ways. If the thorax and pelvis be fixed and both muscles 
act, they will compress the abdominal viscera ; if the thorax 
be fixed, they will approximate the pelvis to it, or if the 
pelvis be stationary, they will draw the thorax forwards. If 
one acts separately, it will rotate the thorax to the opposite 
side, or the pelvis to its own side, or approximate them in a 
lateral direction. Before dissecting up the external oblique, 
the following points should be observed : — 



PARIETES OF THE ABDOMEN. 343 

Fig. 146. 




#vv'/''^^v>r"l 



The Muscles of the Anterior Aspect of the Trunk : on the left side 
THE Superficial Layer is seen, and on the right the Deeper Layer. — 1. 
The pectoralis major muscle. 2. The deltoid; the interval between these muscles 
lodges the cephalic vein. 3. The anterior border of the latissimus dorsi. 4. The 
serrations of the serratus magnus. 6. The subclavius muscle of the right side. 6. 
The pectoralis minor. 7. The coraco-brachialis muscle. 8. The upper part of the 
biceps muscle, showing its two heads. 9. The coracoid process of the scapula. 10. 
The serratus magnus of the right side. 11. The external intercostal muscle of the 
fifth intercostal space. 12. The external oblique muscle. 13. Its aponeurosis; the 
median line to the right of this number is the linoa alba; the ilexuous line to its 
left is the linea semilunaris; and the transverse lines above and below the number, 
the linero transversa^. 14. Poupart's ligament. 15. The external abdominal ring; 
the margin above the ring is the superior or internal pillar; the margin below tho 
ring, the inferior or external pillar; the curved interoolumnar fibres are seen pro- 
ceeding upwards from Poupart's ligament to strcngtlicn the ring. The numbers 14 
and 15 are situated upon the fascia lata of the thigh : the opening immediatoly to 
the right of 15 is the saphenous opening. 10. The rectus muscle of the right side 
brought into view by the removal of tlie anterior segment of its sheath : "■•■" the pos- 
terior segment of its sheath with tho divided edge of the anterior segment. 17. 
The pyramidalis muscle. 18. Tho internal oblique muscle. 19. The oonjoined 
tendon of the internal oblique and transvorsalis descending behind Pi)upart's liga- 
ment to tho pectineal line. 20. Tho arch formed between the lower curved border 
of the internal oblique muscle and Poupart's ligament; it is beneath this arcU that 
the spermatic cord and hernia pass. 



344 OF THE ABDOMEN. 

The Line A Alba, Fig. 146 (13), is a white line extending 
from the symphysis pubis to the xiphoid cartilage. It occu- 
pies the space between the recti muscles, and is formed by 
a blending of the tendinous fibres of the broad muscles of the 
abdomen in the median line. Its breadth increases from 
below upwards. In pregnancy and dropsies of the abdomen, 
it sometimes acquires a greatly increased breadth. The 
umbilicus is situated nearly in its centre. This consists of a 
dense ligamentous substance, to which the integument adheres 
very closely. It is the remains of the umbilical vein and 
arteries of the foetus. When it is necessary to cut into the 
abdominal cavit}^, as in tke high operation of lithotomy, and 
in gastrotomy, or to puncture the parietes, as in ascites, it 
is generally done through the linea alba. 

The Linea Semilunakis, Fig. 146 (13), is a white line situ- 
ated along the external border of each of the recti muscles. 
It is caused by the absence of muscular fibres in this portion 
of the abdominal parietes. 

The LiNE^ Transversa, Fig. 146 (is), extend from the 
linea semilunaris to the linea alba. There are usually four 
or five of them on each side. They are produced by tendin- 
ous intersections in the recti muscles. 

The External Abdominal King, Fig. 146 (15), is an 
opening in the tendon of the external oblique m^uscle, situated 
just above the spine of the pubis. It transmits the spermatic 
cord in the male, and the round ligament in the female. A 
fascia is reflected from its margin down over the spermatic cord. 
This opening and the parts around will be examined in the 
dissection of the inguinal region with reference to hernia. 

The tendon of the external oblique is perforated by nume- 
rous small foramina for the transmission of the cutaneous 
vessels and nerves. The external oblique may be raised by 
detaching it from the ribs and the crest of the ilium, and also 
from Poupart's ligament, if it be not desired to preserve the 
parts in the inguinal region for a special dissection ; in the 
latter case the tendon may be divided by an incision extend- 
ing from the anterior superior spinous process of the ilium 
transversely across to the linea alba. It is sometimes con- 
venient, as when the subject cannot well be turned partly on 
one side, to raise this muscle by making an incision through 



PARIETES OF THE ABDOMEN". 345 

it from near the origin of its upper head, obliquely down- 
wards to the anterior superior spinous process of the ilium, 
nearly in the direction of the fibres of the internal oblique 
muscle, and then turning one flap forwards, and the other 
backwards, detach it from the ribs and the crest of the ilium 
as the dissection proceeds. Whichever mode is adopted, the 
fascia which separates it from the internal oblique should be 
dissected up with it. 

The Obliquus Internus, Fig. 146 (i s), has an extensive 
origin and a more extensive insertion. It arises from the 
fascia lumborum, the crest of the ilium, and the external two- 
thirds of Poupart's ligament. Its fibres diverge so as to 
be inserted into the lower five or six ribs, the xiphoid carti- 
lage, the linea alba, the symphysis pubis, the body of the 
pubic bone, and the linea pectinea. The posterior fibres 
ascend obliquely to the ribs, and the upper part of the linea 
alba ; the middle have a transverse direction, while the ante- 
rior pass forwards and downwards, some to the lower part of 
the linea alba, others to the body of the pubis and the linea 
pectinea. It will be observed that while all the lower and 
anterior part of the external oblique, to the outer side of the 
rectus muscle, is aponeurotic, the corresponding portion of 
the internal oblique is muscular, and that in the upper and 
anterior part the reverse is true. 

The tendon of the internal oblique, above a point midway 
between the umbilicus and symphysis pubis, divides into two 
layers, the anterior of which passes in front of the rectus, and 
unites with the tendon of the external oblique about three- 
fourths of an inch outside of the linea alba, while the posterior 
layer passes behind the rectus and joins the tendon of the 
transversalis muscle. The anterior layer extends higher up 
in front of the rectus than the posterior does behind it. The 
lower part of the tendon does not split, but the whole of it 
passes in front of the rectus. The lowest portion of the 
tendon unites with the corresponding portion of the tendon 
of the transversalis, to form the conjoined tendon^ Fig. 146 
(19), of these two muscles. That part of the conjoined ten- 
don which is inserted into the linea pectinea is placed directly 
behind tlie external abdominal ring, and, as will be seen in 
the dissection of the inguinal region, forms an important part 
in the anatomy of direct inguinal hernia. 



346 OF THE ABDOMEN. 

As no fibres arise from the inner third of Ponpart's liga- 
ment, there is left a space^ Fig. 147 (i i), between it and the 
lower border of the muscle for the passage of the spermatic 
cord. 

The action of the internal oblique muscle is similar in 
some respects to that of the external oblique. When both 
act at the same time, thej will compress the abdominal viscera, 
or approximate the thorax and pelvis. When one acts alone, 
or in conjunction with the external oblique of the opposite 
side, it will rotate either the thorax or the pelvis to its own 
side ; or if it acts with the external oblique of the same side, 
it will bend the thorax to that side, or draw the pelvis up. 

The Cremastee Muscle, which arises from Poupart's 
ligament, in common with the lower fibres of the internal 
oblique, is found in the outer and anterior part of the space 
just named. This muscle accompanies the spermatic cord 
through the external abdominal ring, and down into the 
scrotum, where it forms loops on the tunica vaginalis ; its 
fibres then ascend on the cord, and are inserted into the 
linea pectinea. Some of its fibres are usually lost on the 
tunica vaginalis. 

The fibres of the cremaster are frequently very pale and 
few in number, so that some care is required to separate 
them from the cord. Its use is to draw up and support the 
testicle. 

In raising the internal oblique muscle, the student will 
sometimes experience some difficulty in finding the separation 
between it and the transversalis muscle. This may be done 
most readily by dividing its fibres near the anterior portion 
of the crest of the ilium, where the two muscles are separated 
by the internal circumflex ilii artery. When the separation 
is once found, it is comparatively easy to follow it, especially 
in the upper and posterior part, where the direction of the 
fibres is different. The lower part of the muscle is closely 
connected to the transversalis, and it requires some care to 
separate them. 

The Tra]s"sveesalis, Pig. 147 (e, 7, s, 9), arises from the 
fascia lumborum, the crest of the ilium, the external half of 
Poupart's ligament, and the lower six or seven ribs, where 
it indigitates with the diaphragm. All its fibres, with the 
exception of the lower, or those which arise from Poupart's 



PAEIETES OF THE ABDOMEN. 



847 



ligament, have a transverse direction, and are inserted into 
tlie linea alba. The lower fibres pass forwards and down- 
Fig. 147. 



A Lateral View of the Trunk of 
THE Body, showing its Muscles, and 

PARTICULARLY THE TrANSVERSALIS AB- 
DOMINIS. — 1. The costal origin of the 
latissimus dorsi muscle. 2. The serratus 
magnus. 3. The upper part of the ex- 
ternal oblique muscle, divided in the 
direction best calculated to show the 
muscles beneath, without interfering 
with its indigitations with the serratus 
magnus. 4. Two of the external inter- 
costal muscles. 5. Two of the internal 
intercostals. 6. The transversalis mus- 
cle. 7. Its posterior aponeurosis. 8. 
Its anterior aponeurosis, forming the 
most posterior layer of the sheath of the 
rectus. 9. The lower part of the left 
rectus, with the aponeurosis of the trans- 
versalis passing in front. 10. The right 
rectus muscle. 11. The arched opening 
left between the lower border of the 
transversalis muscle and Poupart's liga- 
ment, through which the spermatic cord 
and hernia pass. 12. The glutaeus maxi- 
raus, and medius, and tensor vaginae 
femoris muscles invested by fascia lata. 




wards, and are inserted into the lower part of the linea alba, 
the body of the pubis and the linea pectinea, forming with 
the internal oblique, the conjoined tendon of the internal oblique 
and transversa lis. The tendon of this muscle is applied to 
the posterior surface of that of the internal oblique, with 
which it passes both behind and in front of the rectus. The 
upper and anterior part of the transversalis is muscular, 
where the corresponding part of the internal oblique is ten- 
dinous. Its principal use is that of a compressor of the 
viscera of the abdomen. 

The fascia Iwnhorum is described in connection with the 
muscles of the back, and should be studied Avhon they are 
dissected. The internal oblique and transversalis muscles 
are sometimes described as arising directly from the vertebrae; 



848 OF THE ABDOMEN. 

tlie former from tlie spinous, and tlie latter from tlie trans- 
verse processes of the lumbar vertebrae. 

To expose tbe rectus, make an incision tbrougli the tendon 
of the external oblique and the anterior lamina of the internal 
oblique, from the cartilage of the sixth rib to the pubis, 
about three-fou.rths of an inch from the linea alba, and paral- 
lel with it ; then dissect these tendons up from the muscle, 
turning one flap inwards and the other outwards. At the 
lower part of the rectus the incision will extend through the 
tendons of the three broad muscles, as they all pass in front 
of that muscle. They are easily separated from the muscle, 
except at the linas transversse, where they are blended with 
the tendinous intersections, from which it will require some 
care to detach them. After exposing the muscle in this way, 
divide it opposite the umbilicus, and reflect one portion up- 
wards and the other downwards, when its relations to the 
tendons of the broad muscles may be examined ; branches of 
the epigastric and internal mammary arteries^ and of the inter- 
costal nerves^ will be seen penetrating it from behind. The 
termination below of the posterior lamina of the tendon of 
the internal oblique, and the tendon of the transversalis, will 
be observed. They generally present quite a distinct semi- 
lunated border, but not always. The tendinous intersections 
are very imperfect behind, and do not usually adhere to the 
sheath of the rectus. 

The Kectus, Fig. 146 (le), arises from the upper border 
of the OS pubis, between the spine and symphysis, by a flat 
tendon. It passes upwards on the side of the linea alba, 
gradually increasing in breadth but diminishing in thick- 
ness, until it reaches the thorax. It is inserted into the car- 
tilages of the fifth, sixth, and seventh ribs, and sometimes 
into the xiphoid or ensiform cartilage. 

The fibres are interrupted in their course by the linem 
transversce ; one of which is placed opposite to the ensiform 
cartilage, one between this and the umbilicus, one at the 
umbilicus, and another lower down. Each presents a zigzag 
line, and only two of them, the one at the ensiform cartilage 
and the one at the umbilicus, extend entirely across the 
muscle. The rectus draws the thorax towards the pelvis or 
the pelvis towards the thorax ; it also acts as a compressor. 
The tendinous intersections connect it with the tendons of 



ANATOMY OF INGUINAL HERNIA. 849 

the broad muscles, and also, when it contracts, prevent its 
bulging so much as it would if its fibres extended the whole 
length of the muscle ; they may, perhaps, augment somewhat 
its power to act. 

The Pyramidalis, Fig. 146 (17), arises from the upper 
surface of the body of the pubic bone, anterior to the rectus. 
It passes upwards, and is inserted into the linea alba two or 
three inches above the symphysis pubis. It is of a trian- 
gular shape, and usually placed in a sheath, formed by a 
splitting of the conjoined tendon of the internal oblique and 
transversalis. It is sometimes absent. The pyramidalis acts 
on the linea alba in a vertical direction. 



Anatomy of Inguinal Hernia. 

The anatomy of the inguinal region may now be examined 
with reference to hernia. Most of the parts contained in it 
have already been noticed, without, however, any particular 
regard to their relations to protrusion of the bowel. They 
will now be described as they appear in the process of dis- 
section. 

The Inguinal Eegion is the triangular space bounded 
above by a line extending from the anterior superior spinous 
process of the ilium to the linea alba, helow by Poupart's 
ligament and the upper border of the body of the pubic 
bone, and internally by the linea alba. 

Dissect the skin from the superficial fascia, and reflect 
it downwards. This dissection should be carried to a short 
distance below Poupart's ligament and down to the dorsum 
of the penis. The superficial fascia contains the arteria ad 
cutem abdominis^ and one or tivo small branches from the 
superior external pudic ; also three or four lymphatic glands, 
which are usually imbedded in it along Poupart's ligament. 
Near the linea alba, the fibres which descend in the fascia to 
form the suspensory ligament of the penis. Fig. 148 (2), should 
be observed. Tlie adipose layer is placed next to the skin, 
Fig. 148 (1, 1), and presents an uneven areolar appearance. 
There is generally considerable fat in this region, espe- 
cially towards the pubis. The membranous layer lies next 
to the tendon of the external oblique. Its under suriacc has 
30 



350 OF THE ABDOMEN. 

a smootTi even appearance. This layer, Fig. 148 (4, 4), alone 
is sometimes spoken of as constitnting tlie superficial fascia. 
The fascia is next to be dissected and reflected down- 
wards in the same manner, and to the same extent, as the 
skin. To preserve the intercoluranar or spermatic fascia^ 
which is reflected from the margin of the external abdomi- 
nal ring down over the spermatic cord, it is better to raise 
the superficial fascia from the ring and cord by insinuating 
the handle of the scalpel or the finger under it, and sepa- 
rating it from the parts beneath. Poupart's ligament, from 
its origin to its insertion into the spine of the pubis, should 
be carefully cleaned, so as to be brought distinctly into view, 
and the cord should be raised for a short distance below the 
ring, so that it may be made more or less tense, and thus 
show more clearly how the intercolumnar fascia is connected 
to the ring. 

To raise the tendon of the external oblique, make an in- 
cision from the anterior superior spinous process of the ilium 
transversely to within about an inch and a half of the linea 
alba, and another from this to the pubis on the inner side of 
the ring ; then dissect it from the internal oblique and the 
cord. The first incision should not be carried beyond the 
junction of the two oblique muscles, as it is only the tendon 
of the external oblique that is to be turned down. If the 
handle of the scalpel be carried along the cord through the 
ring, the intercolumnar fascia will be seen coming fi^^m the 
edges of the ring to surround the cord. Fibres will also be 
observed extending transversely over the cord as it passes' 
through the ring, and for a short distance below it; these 
are sometimes called the intercolumnar hands or fibres^ Fig. 
146 (15). Detach the intercolumnar fascia from the margin 
of the ring, and observe the manner in which it is formed. 

The External Eing, Fig. 148 (13), consists of a slit in the 
tendon of the external oblique, commencing from an inch to 
two inches above, and external to the pubis; the fibres di- 
verge as they pass downwards and inwards to be inserted, 
the lower external into the spine of the pubis with Pou- 
part's ligament, and the uj^j^er internal into the symphysis 
and the pu.bic bone on the opposite side. The term co- 
lumns or pillars, Fig. 148 (14,15), has been applied to these 
fibres. The fibres of the internal column cross those of the 



AKATOMY OF INGUINAL HERNIA. 



851 



corresponding one on the opposite side. The opening thns 
formed is of a triangular shape, with the base towards the 

Fig. 148. 




A View of the External ^Parts concerned in Inguinal and Femoral 
Hernia. — 1, 1. The common integument and adipose tissue of the abdomen turned 
back. 2. The penis, with its suspensory ligament deprived of the integument. 3. 
Integument of the scrotum drawn down. 4,4. Fascia superfieialis of the abdomen. 
6. The same on the thigh. 6. The left spermatic cord covered by the fascia super- 
fieialis. 7. The inguinal glands which are imbedded in the fascia superticialis. 
8. Branch of the external pudic arterj^ 9. Fascia superfieialis turned off the thigh. 
10. Tendon of the external oblique. 11. Linea alba. 12. External oblique muscle. 
3 3, External abdominal ring. 14. Its superior column. 15. Its inferior column. 
16. Testicle covered by the cremaster muscle. 17. Anterior superior spinous pro- 
cess of ilium. 18. Close attachment of the fascia superfieialis on the outside of 
the thigh. 19. Cribriform openings in the fascia lata femoris. 20. Saphenous 
opening. 21. Branch of the saphenous vein. 22. Saphenous vein. 23. External 
femoral ring. 24. Testicle. 



pnbis. Its size varies very much in different subjects. In 
the female it is usually much smaller than in the male. The 
intercoluinnar fibres, which arise generally from Toupart's 
ligament, and extend upwards and inwards across the upper 
part of the triangular opening, convert it into one of a 



352 OF THE ABDOMEN. 

quadrangular shape, also diminisli its size, and bind together 
its columns. There are .other fibres beneath these, which ex- 
tend simply between the columns. 

In cases of hernia, these fibres are stretched so as to allow 
the columns to be separated further than is natural from 
each other. If the hernia be one of long standing, they are 
usually found considerably increased in size. 

The houndaries of the ring, as will now be seen, are the 
columns, one on each side, the body of the pubic bone be- 
tween the insertion of the columns below, and the inter- 
columnar fibres above. 

Beneath the internal column is found a set of fibres 
which arise from the linea pectinea, anterior to the insertion 
of the conjoined tendon of the internal oblique and trans- 
versalis, and pass upwards and inwards to be inserted into 
the linea alba. They form the triangular ligament. Turn 
down the tendon of the external oblique, and make it more 
or less tense with hooks, then carefully remove the areolar 
tissue from the internal oblique and cremaster muscles. The 
lower fibres of the internal oblique are frequently somewhat 
irregular in their position and direction, but a little care will 
suffice to trace them distinctly and loosen them up from the 
cord or separate them from the cremaster. The cord is next 
to be separated from its connections in the inguinal canal, 
and raised up with the tenaculum. The most difficult part 
of this dissection is to preserve the fascia transversalis in the 
posterior wall of the canal, and especially where it is re- 
flected from the internal ring over the cord. The position 
of the cord and the walls of the canal should now be care- 
fully examined. 

The Inguinal Canal, Fig. 150 (3, 3), is about an inch 
and a half in length. It extends from the internal to the 
external ring. Its direction is oblique, from above down- 
wards, from without inwards, and from behind forwards. 
Its boundaries are, in front ^ the tendon of the external ohlique^ 
with a portion of the internal oblique ; below, by Poupart^s 
ligament ; heliind^ by the fascia transversalis externally, and 
the conjoined tencton of the internal oblique and transversalis 
internally; above^ its boundary is more indefinite; it corre- 
sponds to the space between the tendon of the external ob- 
lique and the fascia transversalis, which includes the lower 
borders of the internal oblique and transversalis muscles. 



ANATOMY OF INGUINAL HERNIA. 



853 



The internal oblique and transversalis muscles should now 
be detached from Poupart's ligament, and reflected upwards 

Fig. 149. 




A View op the Deep-seated Parts concerned in Inguinal and Femoral 
Hernia. — 1, 1. Integument nnd adipose tissue. 2. Integument of the scrotum. 
3. Fascia superficialis abdominis and fascia lata femoris turned off. 4. External 
oblique muscle. 5. Its tendon. 6. Linea alba. 7. Lower part of the external ob- 
lique tendon divided and turned back. 8. Right testicle in the tunica vaginalis 
testis. 9. Internal oblique and transversalis muscles. 10. Epigastric artery and 
vein, as placed betvreen the fascia transversalis and the peritoneum. 11. Points to 
the surface of the peritoneum through the internal ring. 12. Cord covered by the 
cremaster muscle lying in the inguinal canal. 13. External ring laid open. 11, 
15. Infundibuliform fascia of the vessels laid open so as to expose them. 16. Pec- 
tineus muscle. 17. The vessels in their sheath. 18. Penis and ligameutum sus- 
ponsovium. 19, 19. Testicle and cord in its entire length. 

from the ftxscia transversalis. By making these muscles 
tense, a good idea may be obtained of the extent and manner 
in which they enter into the formation of the posterior wall 
of the inguinal canal. As the tendon of the transversalis 
curves downwards, it expands, so as to be inserted into the 
linea pectinea, and for some distance into Poupart's li^a- 

30^ 



854 



OF THE ABDOMEN 



ment ; thus it occupies a large portion of tlie space on the 
inner side of the internal ring. 

The Fascia Teansveesalis, Fig. 150 (i i, 12, and 25, 26), 
is thicker and more dense in the inguinal region than in 
any other part of it. It adheres to Poupart's ligament 
throughout its whole extent ; but in front of the femoral 
vessels the fascia is continued an inch or more into the thigh, 
as will be seen in the dissection of the anatomy of crural 
hernia, and in front of the iliacus internus and psoas magnus 
muscles joins the iliac fascia. Internally it lies beneath the 
conjoined tendon and the rectus, being closely connected to 
the tendon of the transversalis. 

The Inteenal Ring, Fig. 150 (1 5), is situated about half 

Fig. 150. 




a View of the Abdominal Muscles and the Abdosiinal, or Inguinal Canal. 
— 1. External oblique muscle of the abdomen. 2. Its aponeurosis. 3. Its tendon 
slit up and turned back to show the canal. 4, 4. Anterior superior spinous processes. 
5. Upper portion of Poupart's ligament. 6. External column of the external ring. 
7. Internal column of the external ring. 8. Intercrossing of the ^tendons of the 
two sides. 9, 9. Bodies of the pubes. 10. Upper boundary of the external ring 
— the line points to the ring. 11, 12. Fascia transversalis. 13. Fibres of the in- 
ternal oblique turned up. 14. Fibres of the transversalis muscle. 15. Points to 
the internal ring — the opening is enlarged for the demonstration, 16. Sartorius. 
17. Fascia lata femoris. 18. Rectus femoris. 19. Adductor longus. 20. Penis. 21. 
Fascia lata of the right thigh. 22. Point where the saphenous vein enters the 
femoral. 23. Fascia lata as applied to the vessels. 24. Insertion of the transver- 
salis muscle on the pubis. 25, 26. Correspond to 11, 12, of the opposite side, and 
indicate the fascia transversalis. 27. Poupart's ligament, turned oft" from the in- 
ternal muscles. 28. Transversalis abdominis. 29. Internal oblique. 30. Rectus 
abdominis. 



ANATOMY OF INGUINAL HERNIA. 855 

way between tlie anterior superior spinous process of tlie 
ilium and the symphysis pubis, and half an inch above Pou- 
part's ligament. It is overlapped by the internal oblique, and 
hence cannot be observed until this muscle is raised. To 
examine this opening, cut through the fascia transversalis a 
short distance above it, and separate the fascia from the 
peritoneum down to where the cord enters the ring, then by 
carrying the handle of the scalpel along the cord, the con- 
tinuation of the fascia over it, and through the canal, is ren- 
dered distinct ; showing that, while there is no opening through 
the fascia from without, there is one from within through 
which the bowel can escape from the cavity of the abdomen. 
The internal ring then is an opening which leads into a 
pouch formed by the testicle carrying before it the fascia 
transversalis in its descent into the scrotum. Sometimes the 
internal ring presents a well defined margin on one side, or 
entirely around it. At other times, it is difficult to demon- 
strate, satisfactorily, the reflection of the transversalis fascia 
over the cord. When the cord is made tense, the fascia trans- 
versalis, as it is reflected from the internal ring, presents a 
funnel-shaped appearance, and hence the name of infundi- 
huliform fascia has been given to this part of it. 

The Epigastric Artery, Fig. 149 (i o), and Fig. 151 (i 3), 
with its accompanying veins, will be found by dividing the 
transversalis fascia on the inner side of the internal ring. It 
lies between the fascia and peritoneum, and crosses the canal 
nearly at right angles. Its distance from the internal ring 
varies from one-fourth to one-half of an inch. 

When the internal surface of the inguinal portion of the 
parietes of the abdomen is examined, tic pouches or fossce are 
observed corresponding to the two rings. These are formed 
by the remains of the hypogastric artery, which, in its course 
from the internal iliac to the umbilicus, projects here into the 
cavity of the abdomen. The peritoneum is reflected over it. 
Sometimes the hypogastric artery is situated a short distance 
to the inner side of the epigastric, when an additional small 
pouch is formed. These lbssa3 cause a greater or less predis- 
position to rupture, according to their depth, by directing the 
bowel against either the internal or external ring. 

The student should now review the parts, the dissection of 
which he has just completed, with reference to hernia. There 



356 OF THE ABDOMEN. 

are two forms of inguinal hernia — direct^ or ventro-inguina\ 
and indirect^ or ohlic[ue. In the oblique form, tlie bowel 
traverses the entire length of the canal passing through both 
rings ; in the direct, it escapes directly through the external 
ring, and does not pass through the canal. 

In Oblique Heexia, the course of the bowel and the dif- 
ferent coverings which it obtains in its descent, are as follows : 
Its course is similar to that of the spermatic cord. As the 
internal oblique overlaps the internal ring, it offers resistance 
to the entrance of the bowel into the canal, hence the bowel 
is forced downwards beneath the lower border of the muscle ; 
in the canal, it is directed downwards, inwards, and somewhat 
forwards ; when it leaves the external ring, its direction is 
towards the scrotum, along the course of the cord. The 
coverings which it gets are, first^ the peritoneum at the inter- 
nal ring; this constitutes the sac; second^ the transverscdis^ 
or infundihuliform fascia^ as it enters the canal; third^^ the 
cremaster muscle^ while passing through the canal ; fourth^ the 
inter coluranar^ or spermatic fascia^ as it goes through the ex- 
ternal ring ; fftli and sixth^ the superficial fascia^ and the in- 
tegument ; the last two coverings it receives entirely outside 
of the canal. 

The cremaster is usually found in front, and on the outside 
of the tumor ; while the cord is generally situated behind, 
and on the inner side. The bowel almost necessarily gets 
between the cord and the cremaster, from their relative posi- 
tion in the upper part of the canal. 

In DiEECT Heexia, the coverings are the same as in indi- 
rect, with a single exception ; the conjoined tendon of the in- 
ternal oblique and transversalis takes the place of the cre- 
master muscle. Sometimes the conjoined tendon is torn, or 
its fibres are separated so as to allow the bowel to pass through 
it ; when this happens, it will not constitute one of the cover- 
ings. 

Another form of direct hernia is sometimes described, in which 
the bowel enters the canal between the epigastric artery and 
the outer border of the conjoined tendon. 

When the bowel passes through the internal ring, but is 
retained in the canal, it is called huhonocele^ or concealed in- 
guinal hernia. In this case, the tendon of the external oblique 
will form one of the coverings. 



VESSELS OF ABDOMINAL PARIETES. 357 

The epigastric artery is tlie principal one to be avoided in 
dividing a stricture in either form of inguinal hernia. This 
is to be done by cutting upwards and parallel to the artery. 

The seat of stricture in indirect hernia may be at the internal 
ring, or where the cord passes under the internal oblique 
muscle, or at the external ring. It occurs most frequently 
at the internal ring, and, next to this, where the cord passes 
beneath the muscle. In direct hernia^ the stricture may occur 
at the external ring, or at the conjoined tendon, especially if 
the tendon be perforated by the bowel. 

There are other forms of inguinal hernia, as scrotal, con- 
genital, and encysted. 

Scrotal^ is when the bowel has descended into the scrotum. 
The tumor in this form of hernia may acquire an enormous 
size. 

Congenital^ is that form in which the bowel descends in the 
tunica vaginalis, while it yet communicates with the cavity 
of the peritoneum. 

Encysted^ is when the bowel descends behind the tunica 
vaginalis, carrying with it a pouch of the peritoneum. 

ThQ fascia transversalis has been observed as forming an 
important part of the anatomy of inguinal hernia. It lines 
the internal surface of the transversalis muscle in other por- 
tions of the abdominal parietes, where it consists of but little 
more than a thin, delicate layer of areolar tissue, and requires 
no particular notice. 

The arteries^ which supply the parietes of the abdomen 
anteriorly and laterally, are the internal mammary, the lower 
intercostal, the lumbar, the internal circumflex ilii, the arteria 
ad cutem abdominis, and the epigastric. 

The Internal Mamm:ary enters the abdomen beneath the 
cartilage of the seventh rib, descends a short distance behind 
the rectus, and then perforates its sheath. AVhile in the 
sheath, it gives branches to the muscle, and sends olY branches 
which go to supply the integuments and the broad muscles. 
They inosculate freely with branches of the epigastric. 

The Intercostal leave the intercostal spaces, and pass 
between the internal oblique and transversalis muscles. They 
inosculate with the internal mannnary, epigastric, and lumbar 
arteries. 



358 OF THE ABDOMEN. 

The Lumbar divide into the posterior and anterior or ab- 
dominal brandies. The latter pass between the middle layer 
of the fascia lumborum and the qnadratus lumborum muscle, 
and thence between the internal oblique and transversalis 
muscles. They anastomose above with the intercostal, in the 
middle with the internal mammary, and below, with the ilio- 
lumbar and internal circumflex ilii arteries. 

The Internal Circumflex Ilii, Fig. 151 (i 4), arises from 
the external iliac just behind, or a little above Poupart's liga- 
ment. It passes upwards and outwards to the anterior supe- 
rior spinous process of the ilium, Avhere it divides into two 
branches. One of these ascends between the internal oblique 
and transversalis, to terminate in the muscles and integument, 
and to inosculate with the intercostal and internal mammary ; 
the other runs along the crest of the ilium, and anastomoses 
with the lower lumbar. The arteria ad cutem abdominis has 
been noticed in connection with the fascia superficialis. 

The Epigastric, Fig. 151 (is), arises from the external 
iliac, just above Poupart's ligament, passes inwards and up- 
wards behind the inguinal canal, and between the fascia trans- 
versalis and peritoneum. It gets behind the rectus, enters 
its sheath, and passes up to the umbilicus, where, or a little 
above, it divides into branches to supply the muscle, and to 
anastomose with the internal mammary. It sometimes gives 
off the obturator and the internal circumflex ilii. Its usual 
branches are, a puhic^ which goes behind the pubis ; a cremas- 
teric^ which enters the inguinal canal, and accompanies the 
spermatic cord to the testicle ; a hranch^ to anastomose with 
the obturator when it arises from the internal iliac ; some- 
times this branch is quite large, and passes near the femoral 
ring. The origin of the epigastric is subject to some varia- 
tion. It may arise from the femoral or from the external 
iliac, some distance above Poupart's ligament. 

The nerves which supply the abdominal parietes are the 
inferior intercostal and the anterior branches of the lumbar. 

The Intercostal Nerves, when they leave the intercostal 
spaces, pass forwards between the internal oblique and trans- 
versalis muscles as far as the rectus, the sheath of which they 
perforate'. Besides muscular branches, they give off two 
sets of cutaneous branches, the anterior and the lateral. The 
former leave the sheath of the rectus, and supply the integu- 



NERVES OF ABDOMINAL PARIETES. 



859 



ment on the front part of the abdomen ; the latter are given 
ofl' about midway between the spine and the linea alba, pass 



Fig. 151. 

5 » 3 17 12 8 9 2 




A View of the Arteries in the Groin of the Left Side in their relatitb 
Positions, the Inguinal Canal being opened. — I. Aponeurosis of the obliquus 
externus muscle. 2. Section of this muscle. 3. Its tendon turned off and upwards. 
4. Its tendon turned downwards and e:xposing the inguinal canal. 5, 6, 7. Subcu- 
taneous arteries. 8. A branch of the arteria ad cutem abdominis. 9. Surface of the 
Obliquus internus muscle. 10. Surface of the transversalis muscle. II. Section of 
the fascia transversalis. 12. Branch of the epigastric artery. 13. Epigastric artery. 
14. Internal circumflex ilii. 15. Lower edge of the transversalis muscle, giving off 
fibres to form the cremaster. 16. Section of tho linoa alba. 17. Rectus abdominis 
muscle. 18. Spermatic cord, entire. 19. An arteriole from the epigastric. 20. 
Another to the fascia. 21. End of the external iliac artery. 22. The femoral 
artery. 23. The profunda femoris. 24. External circumflex. 25. A branch to the 
fascia lata. 26. External pudie artery. 

through the internal and external oblique muscles to the 
skin. When these branches enter the superficial lascia, they 
divide into anterior and posterior lilamcnts, to anastomose 
with each other, and also with the posterior spinal nerves. 

The last dorsal nerve is rehitivcly very large. Its lateral 
cutaneous branch, after perforating the internal and external 
oblique muscles, descends to the crest of the ilium, where it 



860 OF THE ABDOMEN. 

divides into CTitaneous brandies, wliicli are distributed to tbe 
integument in tlae gluteal region. 

The hraiwhes from the lumbar plexus are the superior and 
middle musculo-cutaneous. 

The SuPEKioR MuscuLo-CuTANEous, or Ilio-Scrotal, 
Fig. 178 (3), arises from the upper part of the plexus, per- 
forates the psoas magnus, and runs over the quadratus lum- 
borum muscle to the crest of the ilium, where it gets between 
the transversalis and internal oblique muscles. It divides 
above the crest into an abdominal and pw5zc or an external 
and an internal branch. The abdominal branch has a course 
similar to the intercostal nerves. The pubic division passes 
above Poupart's ligament, and joins the spermatic cord in the 
inguinal canal, passes through the external ring, and is dis- 
tributed to the integument in the pubic region. Sometimes 
it gives off a cutaneous branch, which passes over the crest 
of the ilium, and is lost in the gluteal region. 

The Middle Musculo-Cutain-eous, Fig. 178 (3), has 
nearly the same origin and course as the preceding. It 
generally anastomoses with the superior musculo-cutaneous 
at the upper portion of Poupart's ligament. 

It will be observed that the course of the abdominal nerves 
is, for the most part, the same, while that of the arteries is 
quite different. The parietes of the abdomen are abundantly 
supplied with both nerves and vessels. 



Sect. II. — Dissection of the Cavity of the Abdomen. 

To open the cavity of the abdomen, make an incision from 
the xiphoid cartilage to the umbilicus and a little to one side 
of the linea alba, and another on each side from the umbilicus 
to the anterior superior spinous process of the ilium. 

This cavity is divided into nine regions, Fig. 152, to which 
two others are sometimes superadded. Although these 
divisions are arbitrary, they are still useful for the purpose 
of locating the different organs in the abdomen. They are 
found by making two transverse and two vertical lines. The 
transverse lines extend, the superior from the cartilage of 
the eighth rib on one side to the corresponding rib on the 
opposite side, and the inferior from one anterior superior 



DISSECTION OF CAVITY OF THE ABDOMEN. 361 

spinous process of tlie ilium to tlie other. The vertical lines 
are drawn, one on each side, from the cartilage of the eighth 
rib to the centre of Poupart's ligament. Thus six lateral and 




Surface of the Abdomen, with lines (1, 2, 8, 4) drawn upon it, marking off 
ITS Artificial Subdivisions into Regions. — 5, 5, Right and left hypochondriao. 
6. Epigastric. 7. Umbilical. 8, 8. Tho two lumbar. 9. Hypogastric. 10, 10. 
The right and left iliac. 11. Pubic. 

three middle regions are formed. The lateral, commencing 
above, are the right and left hypochondriac^ the right and left 
lumbar^ and the right and left iliac ; the middle are the epi- 
gastric^ the umhilical^ and the 1 hypogastric. 

The other two are named, the cardiac, and the pidric. The 
former comprises a small space, without any definite bound- 
aries, around the ensiform cartilage; the latter is situated 
just above the pubic bones. 
oi 



862 OF THE ABDOMEK. 

The manner in wliich. these regions are occupied, will be 
better understood after the viscera have been described. "We 
shall give here merely a general account of the location of 
the different organs, preparatory to the examination of the 
peritoneum, and in order that the student may obtain some 
idea of the position of the different viscera in the abdomen 
before he proceeds to the study of them separately. He can- 
not become too familiar with the exact situation and relation 
of each viscus in this cavity. 

In the upper part of the cavity, Fig. 153, and in relation 
with the diaphragm, are the liver^ the stomachy and the spleen. 
The liver alone occupies the left hypochondriac region; a 
part of the liver and stomach are situated in the epigastric 
region ; the spleen and a portion of each of the other organs 
are found in the left hj^pochondriac region, T\iq pancreas is 
situated behind the stomach, extending from the spleen on 
the kft to the concavit}^ of the duodenum on the right. The 
hi<meys are placed in the back part of the lumbar regions. 
The ccecum is in the right iliac region. The colon commences 
at the caecum, passes upwards through the right lumbar 
region to the liver, then turns to the left and goes across 
the upper part of the umbilical, below the liver and stomach, 
to the left lumbar region, where it is in contact with the 
spleen; thence it descends, in front of the kidney, to the 
left iliac region, where, after forming the sigmoid flexure, 
it enters the pelvis and terminates in the rectum. The 
duodenum begins at the right extremity of the stomach, 
proceeds about two inches and a half to the right between the 
liver and colon, turns downwards behind the colon, and then 
passes to the left through the mesentery, to terminate in the 
jejunum. The remainder of the small intestine, consisting of 
the jejunum and ihurn^ is found principally in the umbilical 
region, and terminates in the c^cum. 

The Peeitoxeum is the largest serous sac in the body. It 
presents two surfaces, an external and an internal; the latter 
is smooth and polished, being constantly lubricated with a 
serous exhalation; XkvQ former^ or external, is everywhere ad- 
herent. It is divided into a visceral and a parietal portion; 
and different parts of these, as will be seen, are designated by 
different names. 

Above the umbilicus, and in the median line, the parietal 



DISSECTION OF CAVITY OF THE ABDOMEN. 363 

portion is reflected upon tlie remains of the umbilical vein 
of tlie foetus, and forms the suspensory ligament of the liver. 
Below the umbilicus it presents three folds which correspond, 
in the middle, to the urachus, and on the sides to the umbili- 
cal arteries of the foetus. In some parts it adheres closely to 
the abdominal parietes, while in others, as in the lumbar and 
iliac regions, more or less loose areolar tissue intervenes. 

The visceral portion is rendered somewhat complex by its 
numerous reflections. To understand it properly, the student 
cannot rely upon a mere description of it ; he must examine 
it for himself. The best mode of doing this is to study it in 
its connections with the organs which it invests, and from 
which it is reflected to the parietes. It is in this way that 
we shall describe it. 

If the liver be examined, it will be found that the perito- 
neum covers nearly the whole of its exterior surface, includ- 
ing a portion of the gall-bladder; and that it is reflected from 
it at four different places. From its upper and anterior 
surface in the median line it is reflected to the diaphragm, 
so as to form a fold which extends from the ligamentum teres 
or the remains of the umbilical vein of the foetus, which it 
includes, to the posterior border of the liver. This fold is 
called the suspensory ligament^ and indicates the dividing line 
between the right and left lobes of the liver. At the poste- 
rior border it is reflected to the diaphragm, and forms first 
the coronary and then the right and left lateral ligaments; of 
the last two the right one is short, and attaches the right 
lobe closely to the diaphragm, while the left is longer, and 
allows the left lobe a considerable degree of mobility inde- 
pendently of the diaphragm. From the under surface it 
is reflected in three laminae. The anterior tico form a fold, 
which contains, in its right border, the hepatic artery and duct^ 
the portal vein, the hepatic plexus of nerves, and the deep-seated 
lymphatics of the liver, and below, the stomach. This fold 
between the liver and the stomach, is named the gastro-hepatic 
omentum, Fig. 151: (9). These two laminre leave the con- 
vex border of the stomach, pass down in front of the trans- 
verse colon, without adhering to it, and descend to the lower 
part of the abdomen, Fig. 153 (27, .27), where they are re- 
flected on themselves ; they then pass upwards to the trans- 
verse colon, to inclose which they separate, and then reunite and 
go backwards to the spine, forming the transverse mcso-colon; 



d64: OF THE ABDOMEN. 

having readied the spine, they again separate, the one to de- 
scend, to invest the small intestines, and form the mesentery^ 
the other to ascend over the lower portion of the duodenum, 
and the pancreas to the under surface of the liver. 

Thus it will be seen that the posterior lamina of the gastro- 
hepatic or lesser omentum passes down behind the stomach 
to near the lower part of the abdomen, and returns again to 
the liver, passing over the transverse colon, a part of the duo- 
denum, and the pancreas. It is this lamina which forms the 
lesser peritoneal sac. Although applied to the anterior lamina 
from the liver to the spine, except where they separate to 
inclose the stomach and colon, they are nowhere continuous, 
except at the right border of the gastro-hepatic omentum. 
If the student will examine this horder, he will find that the 
two laminae of the gastro-hepatic omentum are here con- 
tinuous around the hepatic vessels, and that behind it is 
an opening which leads into the lesser sac or pouch formed 
by the posterior lamina. This opening is called \h.Q foramen 
of Winslow, Fig. 154 (9). 

It is through i\iis foramen only that the posterior surface of 
the stomach, the anterior surface of the transverse colon and 
the pancreas, and the lobus Spigelii can be reached with- 
out destroying the continuity of the peritoneum. It has, in 
front, the hepatic vessels, heliind, the ascending vena cava, 
above, the lobus Spigelii, and helow, the superior transverse 
portion of the duodenum. 

The omentum majus, or gastro-colic omentum,. Fig. 153 (27, 
27), consists of the two laminae which have already been de- 
scribed as passing down from the convex border of the 
stomach in front of the small intestine, and again ascending 
to the transverse colon. It has been compared to an empty 
sac within a sac, and although thin and transparent, it consists 
of two anterior and two posterior laminae. In the lower part 
of it the laminae adhere so closely to each other that it is 
difficult to separate them, and not unfrequently it presents a 
cribriform or net-like appearance. It usually descends lower 
on the left than on the right side. Between its laminas are 
found vessels, and more or less adipose substance. Its most 
probable use is to facilitate the movements of the convolu- 
tions of the small intestine on themselves and on the ab- 
dominal parietes. In some cases, it extends but a very little 
distance below the colon. 



DISSECTION OF CAVITY OF THE ABDOMEN. 365 

Tlae whole of the spleen^ except the hilum, or fissure, 
through which the vessels enter it, is invested by the peri- 
toneum. It is reflected from the spleen along the splenic 
vessels to the left extremity of the stomach, where it becomes 
continuous with the lamina which passes over the anterior 
surface of that organ. This portion of it is designated the 
g astro-splenic omentum. 

Below the spleen, the peritoneum is continued down over 
the left extremity of the transverse colon and the descending 
colon^ forming the descending meso-colon. From the meso- 
colon it is reflected on the left to the parietes, and on the right 
it is continuous with the anterior lamina of the omentum 
majus and the mesentery ; lower down it is reflected over the 
sjjine, the aorta^ the vena cava^ the ureter and iliac vessels. It 
lies in front of the left kidney^ from which it is usually sepa- 
rated by fat, areolar tissue, and partly by the colon. 

From the posterior border of the right lobe of the liver 
it is reflected downwards over the right kidney^ the superior 
transverse portion of the duodenum^ the right extremity of the 
transverse colon^ the commencement of the inferior transverse 
portion of the duodenum^ the ascending colon and ccecuin^ form- 
ing the ascending meso-colon and the meso-coecum. On the left^ 
it joins the anterior lamina of the omentum majus and the 
mesentery ; on the right^ it joins the parietal portion. The 
caecum is sometimes almost wholly covered by peritoneum. 

The lamina of the ascending and of the descending meso- 
colon, above the sigmoid flexure,' are separated some dis- 
tance apart, so as to leave the posterior aspects of these 
portions of the colon uncovered by peritoneum. Thus it 
is that the large intestine can be punctured without wound- 
ing the peritoneum. The lamina? of the transverse meso- 
colon and of the sigmoid flexure in the left iliac region 
are applied to each other so as to leave just space enough 
for the vessels and nerves to reach the parietes of the in- 
testine. 

The difference in the length of the moso-cohi should be 
observed. That of the transverse colon as well as that of 
the sigmoid flexure are usually several inches in length, al- 
lowing a considerable degree of mobility to those parts of 
the large intestine. 

In the pelvis, the peritoneum is reflected over the upper 

31* 



366 OF THE ABDOMEX, 

part of tlie rectum to the parietes forming the meso-reciurn ; 
it also covers the wp-per ?iRdi posterior part of the hladder^ from 
which it is reflected behind to the rectmn, and laterallY and 
anteriorly to the parietes, forming the posterior lateral ligor- 
merits of that organ. 

In the female it covers the oMerior upper tiro-tidrcls of the 
uterus^ and the Tvhole of it, posteriorly, including the upper 
and posterior part of the vagina. As it is reflected from the 
uterus it forms several folds, as the hroad ligaments laterally, 
the recto-uterine behind, and the vesico-uterine in front. 



EELATIOXS of the ABDO:NnXAL YlSCEEA. 

Before describing the special anatomy of the abdominal 
viscera, we shall give a brief description of their relations 
to each other and to the surrounding parts. It is only in 
the dissecting-room that the student will be able to acquire 
this knowledge in a manner that will make it satisfactory 
and useful to himself. The study of the special anatomy of 
most of the organs will require their removal from the ab- 
dominal cavity, which must necessarily destroy their relations 
to contiguous parts. 

In the upper part of the abdomen, Fig. 158, there are 
three organs, whose relations to the diaphragm, and through 
it to the lungs and heart in the thorax, should be carefully 
observed. These are the liver^ the storao.ch^ and the spleen. 
Of these only the liver has any direct relation to the right 
lung. It is received deeply into the concavity of the lung, 
ascending in expiration as high as the fifth, or even the 
fourth intercostal space. It necessarily rises and descends 
alternately in expiration and inspiration. 

Both the liver and the stomach are placed in apposition 
with the central part of the diaphragm, and are separated 
from the heart only by the cordiform tendon and the ad- 
herent portion of the pericardium. 

The spleen^ the stoma.cli^ and a small portion of the left lobe 
of the hver occupy the concavity of the left part of the dia- 
phragm, and consequently are in relation with the left lung. 
They do not ascend quite so high as the liver does on the 
right side. 

It will be seen from the position of the liver that if it 



RELATIONS OF THE ABDOMINAL VISCERA. 367 

should become agglutinated to the diaphragm, a hepatic 
abscess might open into the pleural cavity above, or if adhe- 

Fig. 153. 




A View op the Viscera op the Chest and Abpomen, in their Natural 
Position, as given by the removal op the Anterior Parietes of each Ca- 
vity. — 1, 2. The ribs forming the side of the chest 3. Fatty tissue in the ante- 
rior mediastinum. 4, 4. The section of the pleura of each side. 5. The pericar- 
dium inclosing the heart. 6, Superior lobe of the right lung, 7. Inferior lobe of 
the right lung, 8. The fissure which separates them. 9. Upper lobe of the left 
lung. 10. Lower lobe of the left lung. 11, Fissure between them. 12. A trans- 
verse section of the diaphragm. 13. Superior face of the right lobe of the liver. 
14. Superior ftiee of the left lobe of the liver. 15. Lower end of the gall-bladder. 
10. Inferior and anterior edge of the liver. 17. Round ligament of the liver. 18. 
Suspensory ligament of the liver. 19. Anterior face of the stomach, 20. Its 
greater extremity. 21. Its lesser extremity. 22. Its lesser curvature. 23. Its 
greater curvature. 24, The pylorus. 25. The duodenum. 2(5. A part of the gas- 
tro-hcpatic omentum. 27, 27. The majus omentum. 28. 28. Convolutions oftho 
small intestines, seen through this omentum. 29. The spleen. 30, 30. The large 
intestines. 31, 3L Parietes of the abdomen turned down. 



368 OF THE ABDOMEN, 

sions between the diaphragm and the lung should exist at 
the same time, the pus might find its way into the bronchial 
tubes. An effusion into the cavity of the pleura would 
press the liver downwards ; or, in ease of enlargement of 
the liver, the lung might be pressed upwards. 

Abscesses of the liver may open externally through the 
intercostal spaces, or lower down through the anterior parietes 
of the abdomen. The reflections of the pleurae and of the pe- 
ritoneum are such, that if an instrument should be carried 
horizontally backwards through the sixth or seventh inter- 
costal space, it would pass through \h.Q former eight times and 
the latter four times. 

It is mainly through the mediu.m of the liver and stomach 
that the impulse of the heart is transmitted to the abdomi- 
nal parietes. The portions of these organs which correspond 
to the cordiform tendon of the diaphragm are subjected to 
scarcely any upward or downward movement. 

The spleen is pressed on by the contraction of the dia- 
phragm. This sometimes gives rise to pain in this organ 
after running. If it be enlarged, the pain may be greatly in- 
creased. It is in relation with the ninth, tenth, and eleventh 
ribs, through the medium of the diaphragm, and may be 
pressed on by them. The position of the spleen is deep in 
the left hypochondriac region, and cannot be reached by 
pressure upon the external surface of the body, except 
through the lower ribs, or by pressing the hand upwards 
underneath them. 

The under surface of the liver is in relation with the right 
kidney, the upper and right part of the colon, the superior 
transverse portion of the duodenum, the stomach, and the 
pancreas. Hence hepatic abscesses may open into the colon, 
the duodenum, or the stomach. The gall-hladder rests on 
the pylorus or duodenum and the colon, which are frequent- 
ly stained with bile in the dead subject ; gall-stones some- 
times escape by ulceration into the colon or duodenum. It 
corresponds very nearly to the cartilage of the eighth or 
ninth rib, and is about two inches and a half to the right of 
the median line or linea alba. 

The anterior surfax^e of the stomach is in relation with the 
left lobe of the liver, the diaphragm, and the anterior walls 
of the abdomen. The posterior surface corresponds to the 
pancreas, the splenic vessels, the solar plexus, and the aorta. 



RELATIONS OF THE ABDOMINAL VISCERA. 369 

Its left extremity projects from two to three Indies to the left 
of the cardiac orifice, is in contact with the concavity of 
the spleen, and is just above the left kidney and renal cap- 
sule. Its cardiac orifice is situated below the diaphragm, and 

Fig. 154. 




A View of the same Viscera, after the removal op the Fat in the 
Chest and the Omentum Majus of the Abdojien. The Liver also has been 

TURNED BACK TO SHOW ITS UnDER SuRFACE AND THE LesSER OmENTUM. — 1. Tho 

great bloodvessels of the heart. 2. Tho lungs of each side. 3. The heart. 4. 
The diaphragm. 5. Under surface of the liver. 6. The gall-bladder. 7. Union of 
the cystic and hepatic ducts to form tho ductus choledochus. 8. Anterior faco of 
the stomach. 9. The gastro-hepatic. or lesser omentum. A female catheter has 
been passed through the foramen of Winslow, and is seen Ihrougli tho omentum. 
10. Gastro-colic, or greater omentum, cut oil', so as to show the small intestines. 11. 
Tho transverse colon, pushed slightly downwards. 12. Its ascending portion, also 
pushed down. 13. Small intestines. 14. Tho sigmoid liexuro. lj.° Appoudicula 
vcrniiformis. 



370 OF THE ABDOMEN. 

behind the posterior border of the left lobe of the liver, near 
the median line. The pyloric orifice is situated about three 
or four inches lower down in the abdomen, and to the right 
side. It corresponds nearly to the position of the gall- 
bladder. It is much nearer to the anterior parietes than the 
cardiac orifice, and hence tumors which have their seat near 
the pyloric orifice can be more easily felt than when near 
the cardiac. The junction of the stomach and duodenum is 
indicated by a circular constriction. The superior or concave 
horder is occupied by the lesser omentum, and looks towards 
the liver. The convex horder is in relation with the meso- 
colon behind, and is occupied with the commencement of the 
gastro-colic omentum. The position of the stomach is altered 
somewhat when it is distended. Its anterior surface then 
looks upwards, and its posterior downwards ; its borders are 
also changed, the convex one is directed forwards, and the 
concave backwards. 

The student may now proceed to examine the connections 
of the duodenum. This can be done more satisfactorily if 
it, together with the stomach, be moderately inflated. For 
this purpose, a pipe may be inserted into the upper part of 
the jejunum. 

The duodenum presents three parts for study; a superior 
transverse^ a descending^ and an inferior transverse portion. The 
first division commences at the pylorus, and extends about 
two inches upwards, backwards, and to the right side, in 
contact with the liver and gall-bladder. It is covered on 
both sides by peritoneum, and consequently is quite mov- 
able. The vena portse and the ductus choledochus communis 
pass behind it. 

The descending portion passes downwards about three inches, 
having the transverse colon in front and the concave border 
of the kidney and its vessels behind, the ascending colon on 
the outer side, and the head of the pancreas on the inner side. 
This portion is only partly covered by peritoneum. The 
biliary and pancreatic ducts open into its inner and posterior 
part near the middle. 

The third division is situated between the laminae of the 
meso-colon. It passes from the right to the left across the 
right crus of the diaphragm, the vena cava, and the aorta. 
The pancreas is placed above, and partly separated from it 
by the mesenteric vessels. It presents a slight bulging below 
the transverse colon, and near its commencement. Its ter- 



EELATIONS OF THE ABDOMINAL VISCERA. 371 

mination in the jejunum is seen on the left side of the me- 
sentery. Like the descending portion, it is only partly covered 
by peritoneum. 

The middle and lower portions of the duodenum are so 
fixed by their connections that they cannot well be displaced 
unless by the development of a tumor. The first portion 
may be drawn down more or less by the stomach. 

The small intestine below the duodenum consists of the 
jejunum and ileum. It is convex anteriorly and concave pos- 
teriorly. It occupies the umbilical and hypogastric regions, 
and extends laterally into the lumbar and iliac. It is at- 
tached to the posterior wall of the abdomen by the mesentery^ 
which extends obliquely across the spine from the left lum- 
bar region downwards to the right iliac. The mesentery is 
short at its extremities, but much longer in the middle, where 
it allows a great degree of mobility to the corresponding 
portion of the intestine. It contains between its laminae the 
mesenteric vessels, nerves, and glands. The convolutions of 
the jejunum and ileum have no regular form. They are in 
contact with the anterior parietes of the abdomen, except 
when the omentum majus covers them, and are separated 
from the viscera above by the transverse colon and its meso- 
colon. They are usually found partly lodged in the pelvis, 
where they are in contact with the rectum and bladder, and 
in the female with the uterus. Their mobility is such that 
they can adapt themselves to any changes that may take 
place in the contiguous organs, or in the condition of the 
abdominal cavity. 

The large intestine consists of the ccecum^ colon, and rectum. 

The ccccum is situated in the right iliac region. It is 
attached to the iliac fossa by the meso-ca3Cum. It varies in 
length from an inch and a half to three or four inches. It 
rests on the iliac fascia, and has, in front and on the inner 
side of it, the convolutions of the small intestine; when dis- 
tended, it is in contact with the anterior abdominal parietes. 
The ajppendix vermiformis ca'ci is joined to it inferiorly. It 
is a small, hollow, cylindrical body, from two to four inches 
in length, and bound down by a fold of the peritoneum. The 
small intestine joins the large at the junction of the Ci\^cum 
and colon. 

The colon is divided into the ascendmg, the transverse^ and 
the descending 2'>ortions ; the latter includes the sigmoid jlexure. 

The first division ascends throuo'h the ri^ht lumbar region 



872 OF THE ABDOMEN. ^ 

to the nnder surface of tlie liver. It lies at first on the an- 
terior layer of the fascia lumborum, and then on the kidney; 
the vertical portion of the duodenum and the convolutions 
of the small intestine are placed on the inner side, and the 
latter also in front of it when it is empty. Externally, it is 
applied to the wall of the abdomen. The lower part of it 
can be reached through the lumbar region without impli- 
cating the peritoneum. 

The transverse colon^ sometimes called the arch of the colon, 
extends from the inferior surface of the right lobe of the liver 
to the spleen in the left hypochondriac region, where it is 
continuous with the descending colon. Its position is below 
that of the liver, stomach, and spleen. As it crosses the 
abdomen, it has to ascend to reach the spleen, as that organ 
is so much smaller than the liver. It is separated from the 
anterior abdominal parietes by the descending laminae of the 
omentum majus. The small intestine is below, and the 
meso-colon behind it. It frequently has attached to it 
numerous small pouches of peritoneum, which contain fat. 
These are called the appendices epiploicm. They are not 
known to perform any function. The transverse colon is 
allowed, from its position and attachments, a greater degree 
of mobility than any other portion of the intestinal canal; 
hence its direction and situation are subject to marked 
changes. It is sometimes met with passing down into the 
hypogastric region, and again ascending to the left hypochon- 
driac. 

The descending colon passes down through the left lumbar 
to the left iliac region. Its relations are similar to those of 
the ascending colon. It is somewhat longer, and is not as 
mucE covered by the peritoneum, hence it can be perforated 
with less danger of wounding the peritoneum ; its posterior 
or non-peritoneal surface also corresponds to the fascia lum- 
borum higher up above the crest of the ilium, on account of 
the left kidney being situated higher than the right. 

The sigmoid flexure is generally found partly in the left iliac 
fossa and partly in the pelvis. It forms a double curve. From 
the length of its meso-colon it has more mobility than any other 
portion of the large intestine, except the transverse colon. 
Its direction is downwards, and from left to right. It is sub- 
ject to much variation in the length, direction, and position 
of its flexures. When it is distended with gas or fecal matter, 



RELATIONS OF THE ABDOMINAL VISCERA. S73 

it is in direct apposition with the walls of the abdomen, and 
can be felt during life through the parietes; but when it is 
emptj, the convolutions of the small intestine usually inter- 
vene. It terminates in the rectum opposite the left sacro- 
iliac symphysis, without any precise line of demarcation. 

Only the superior part of the rectum can be observed with- 
out a dissection of the pelvis. Its relations to the bladder 
and to the uterus, in the female, may be noticed at the present 
time, leaving the study of it until the pelvic viscera are 
examined. 

The parts surrounded by the capsule of Glisson, in front 
of the foramen of Winslow, should now be dissected. 

They consist of the ductus clioledoclius communis on the right 
side, the hepatic artery on the left, and the portal vein between 
and behind the duct and artery. The hepatic plexus of nerves 
accompanies the artery. From the ductus choledochus the 
hepatic duct may be traced to the transverse fissure of the 
liver, and the cystic duct towards the gall-bladder. The ductus 
choledochus is about two inches and a half in length. Its 
direction is downwards, backwards, and a little to the right. 
It passes behind the duodenum to reach the inner and central 
part of its descending portion. It accompanies, for a short 
distance, the pancreatic duct, a groove formed in the sub- 
stance of the pancreas. It perforates the coats of the duo- 
denum, as will be seen at another time, obliquely. The 
ductus choledochus varies much in size in different subjects. 
It sometimes acquires very great size from the detention of 
bile. 

The pancreas may be exposed by dividing the descending 
laminae of the omentum majus a little distance beloiw the 
convex border of the stomach and turning that organ up- 
wards. The middle portion of it is brought into view by 
simply dividing the gastro-hepatic omentum. 

The pancreas is situated behind the stomach, and is covered 
by the ascending lamina of the transverse mcso-colon. It 
extends from the spleen to the descending portion of the duo- 
denum, being from six to seven inches in length. The duo- 
denal extremity, from its size, is sometimes called the head of 
the pancreas. It fills the concavity of the duodenum, and 
adheres closely to it. The splenic cud is named the tail^ and 
the middle part the hodij. The coeliac artery projects forwards 
32 



374 OF THE ABDOMEN. 

above its u]^per horder^ and gives off tlie splenic, gastric, and 
hepatic arteries, both, of wbicb run along its npper edge, the 
former to tlie spleen, and the latter to the liver. It corresponds 
hehind to the vena portse, the vena cava, the aorta, the crura 
of the diaphragm, and also to the superior mesenteric artery 
and vein, which form in it quite a deep sulcus. Its left or 
s'plenic extremity rests on the superior extremity of the left 
kidney and the supra-renal capsule. 

The excretory duct of the pancreas runs the whole leng-th 
of the gland. It joins the ductus choledochus a short distance 
before the latter opens into the duodenum, so that the two 
ducts open by a common orifice. Sometimes there is a small 
pancreatic duct which opens either into the large one, or sepa- 
rately. It is better that the duct of the pancreas should be 
examined, at least partially, before the gland is removed 
from the abdomen. 

If the pancreas becomes enlarged from disease, it may press 
npon the vessels beneath it, retarding the circulation through 
them. The arteries may, at the same time, communicate a 
pulsatory movement to the tumor, which might give rise to 
the impression that there was an aneurism. Its relations to 
the stomach are important. It may, by chronic inflamma- 
tion, become so agglutinated to the posterior wall of that 
organ, that when it is perforated by ulceration the pancreas 
will prevent the escape of its contents. Scirrhus of the pan- 
creas might be mistaken for that of the pylorus. 

The kidneys are situated in the lumbar regions^ the left a 
little higher than the right. Each lies on the anterior lamina 
of the fascia lumborum, which separates it from the quad- 
ratus lumborum muscle, and on the diaphragm by which it 
is separated from the lower two or three ribs. The ascend- 
ing colon lies in front of the right, and the descending colon 
in front of the left. The liver is in relation with the upper 
extremity of the right, and the spleen with that of the left. 
Each one is separated from the spine by the psoas magnus, 
and the right one also by the vertical portion of the duode- 
num. They are usually surrounded by considerable fat and 
areolar tissue. Sometimes the peritoneum comes in direct 
contact with their anterior surfaces ; the colon, in that case, is 
placed to the inner side of them. The supra-renal capsule is 
situated on the upper extremity of the kidney. 

The ureters should now be traced from the kidneys into 



VESSELS AND NERVES OF ABDOMINAL VISCERA. 375 

the pehds. Each one lias a direction downwards and inwards 
along tlie psoas magnus, until it reaches the common iliac 
artery, which it passes over, and also the sometimes external 
iliac, to enter the pelvis. It is covered by the peritoneum, 
and has the spermatic vein and artery crossing over, and the 
genito-crural nerve passing behind it. 

Before the viscera are removed from the abdomen for dis- 
section, the vessels and nerves which supply them should be 
carefully examined. The arteries are, the coeliac, the superior 
and inferior mesenteric, the capsular, and the renal. The 
veins correspond very nearly to the arteries ; and all of them, 
except the renal, belong to the portal system. The nerves 
are derived from the pneumogastric and the sympathetic. 

In the dissection of the vessels of the abdominal viscera, 
no rule can be laid down for the guidance of the student that 
will be of much service to him. Before commencing their 
dissection, he should read carefully a description of each one 
of them, and ascertain very nearly its origin, position, and 
direction. He will then be able to place the parts in the 
position most favorable for getting at and tracing them. In 
exposing the coeliac artery and its branches, it may be found 
necessary to change the position of the stomach several times ; 
and the same may be required in the case of organs concerned 
in the dissection of other arteries. In tracing the vessels which 
are distributed to the stomach and intestines, much assistance 
may be derived from a partial inflation of these organs. 

As the arteries are, for the most part, accompanied by veins 
and plexuses of nerves which must be dissected at the same 
time, they will be described in connection. It should be re- 
marked here, that if the student should wish to acquire a 
thorough and minute knowledge of the nerves in the abdo- 
men, he should obtain a subject for this purpose alone. 

The Cgeliac Artery, Fig. 155, 5, and Fig. 159 (2), is given 
off from the aorta, just below the opening in the diaphragm, 
and between the crura of that muscle. It is from one-half 
to three-fourths of an inch in length, and projects almost 
directly forwards. It is surrounded by the solar plexus, and 
has one of the semilunar ganglia on each side of it. 

The Solar Plexus, Fig. 142 (ao), consists of a network 
of nerves, placed in front of the crura of the diaphragm and 
the aorta, and around the coeliac artery. It receives fda- 



376 OF THE ABDOMEN. 

ments from tlie splanclmic nerves and the right pneumogas- 
tric nerve. It gives o£P the hepatic, the splenic, the gastric, the 
phrenic, the superior mesenteric, and the renal plexuses. Each 
one of these plexuses should be observed, when the artery 
which it accompanies is dissected. 

The Semilunar Ganglia are the largest in the body. 
They are situated one on each side of the solar plexus, be- 
hind and above the supra-renal capsule, and resting on the 
diaphragm and aorta. Although called semilunar, they are 
very irregular in shape, frequently consisting of several small 
masses connected by filaments. The great splanchnic nerves 
terminate in them. They are joined to each other by the 
solar plexus. 

The coeliac artery has no corresponding vein. It divides 
into three large branches, the splenic, the gastric, and the- 
hepatic. It is sometimes called the coeliac axis; and its three 
branches the tripod of Sailer. 

The Splenic Artery, Fig. 155, i, runs along the upper 
border of the pancreas to the hilum of the spleen, where it 
divides into several branches to be distributed to that organ. 
It is much longer than the distance from its origin to the 
spleen, hence it is very tortuous, although nearly horizontal 
in its general direction. It furnishes branches to the pan- 
creas and stomach. 

The pancreatic branches are given off to the pancreas as it 
runs along the upper border of the gland. Near the left ex- 
tremity, one branch, larger than the others, penetrates the 
gland, and, joining the duct, accompanies it to the right. 

The left gastro-epiploic. Fig. 155, h, turns to the right, and 
runs some distance along the convex border of the stomach, 
where it anastomoses with the right gastro-epiploic artery. 
In its course it sends branches to both sides of the stomach 
and to the omentum majus. 

The vcLsa hrevia consist of several branches, which arise 
from the terminal divisions of the splenic artery. They go 
to the left extremity of the stomach, where they anastomose 
with branches of the gastric artery. 

The Splenic Yein, Fig. 157, h, commences in the hilum- 
of the spleen, by the union of branches which originate in 
the cells of that organ. It receives branches which corre- 



VESSELS AND NERVES OF ABDOMINAL VISCEEA. 377 

spond to those given off by the splenic artery to the stomach 
and pancreas. The inferior mesenteric vein also empties into 

Fig. 155. 




The Viscera of the Uppek Part of the Abdomen, with the Cceeiac Artery 
AND ITS Branches, ARE REPRESENTED IN THIS SKETCH. — 1. Liver. 2. Gall-bladder. 
3. Stomach. 4. Its pyloric end. 5. Pancreas. 6. Spleen. 7. Great omentum. 
A. Aorta, a. Phrenic arteries, h. Coeliao. c. Coronary of stomach. (L Hepatic, 
e. Superior pyloric. /. G astro-duodenal, g. Right jrastro-epiploic. h. Cystic 
artery to gall-bladder, i. Splenic. Jc. Loft gastro-epiploic. 



it. It is situated, in its course, behind the splenic artery and 
the pancreas. It is not tortuous like the artery, but is 
much larger. It joins the superior mesenteric vein beneath 
the pancreas, and a little to the left of the ascending vena 
cava. 

32* 



378 OF THE ABDOMEN. 

The Splenic Plexus is derived from the coeliac or solar 
plexus. It accompanies the splenic artery, upon which its 
filaments may be readily traced. It gives off filaments to the 
pancreas and to the left extremity of the stomach. The 
latter form the left gastro-epvploic plexus^ which accompanies 
the artery of the same name. The plexus terminates in the 
substance of the spleen. 

The G-ASTEic or Superior Coronary Artery, Fig. 155, 
c, passes between the laminse of the gastro-hepatic omentum 
to the cardiac orifice of the stomach, it then turns to the right 
and runs along its upper or concave border to near the pylo- 
rus, where it anastomoses with the superior pyloric, a branch 
of the hepatic. It gives off branches to both sides of the 
stomach and to the lower part of the oesophagus. 

The siLjierior coronary vein commences at the lower part of 
the oesophagus and left extremity of the stomach, and ac- 
companies the coronary artery along the upper border of 
the stomach to the pylorus, where it empties into the vena 
portas. It receives in its course branches from both sides of 
the stomach. 

The coronary jolexus is formed by filaments derived from 
the upper part of the solar plexus, but chiefly from the 
pneumogastric on the right side. Its filaments are distri- 
buted to the stomach along with the branches of the coronary 
artery. 

The Hepatic Artery, Fig. 155, tZ, goes transversely to 
the pylorus, and then enters the capsule of Glisson in the 
right border of the gastro-hepatic omentum, and passes up- 
wards to the transverse fissure of the liver. It is smaller than 
the splenic, but larger than the gastric artery. It gives off 
the following branches : — 

The superior pyloric^ Fig. 155, e, arises near the pylorus, 
runs a short distance on the upper border of the stomach, 
and anastomoses with the superior coronary artery ; it sends 
twigs to the sides of the stomach. 

The gastro-duodenal.^ Fig. 155, /, passes downwards be- 
hind the duodenum near the pylorus, and divides into the 
pancreatico-duodenal and the right gastro-epiploic. Before . 
it divides, it gives off the inferior pyloric hranclies to the 
pylorus. 

The pancreatico-duodenal is distributed to the head of the 



VESSELS AND NERVES OF ABDOMINAL VISCERA. 379 

pancreas and the diiodennm, between whicli it runs some 
distance. It also gives off a branch, to anastomose with, one 
from the superior mesenteric artery. 

The right gastro-epijploic^ Fig. 155, ^, turns to the left, runs 
along the convex border of the stomach, and anastomoses 
with the left gastro-epiploic. It gives ascending branches to 
both sides of the stomach, and descending to the omentum 
majus. 

The cystic artery^ Fig. 155, A, arises from the right division 
of the hepatic in the transverse fissure of the liver. It goes 
to the gall-bladder, and divides into two branches, which ra- 
mify on its sides. 

There is no vein that corresponds to the hepatic artery. 
The veins which accompany its branches empty into the 
vena portse. The blood which is conveyed to the liver by 
the hepatic artery enters plexuses formed by the portal vein 
in the substance of that organ. 

The Hepatic Plexus follows both the hepatic artery 
and portal vein to the liver; hence it has been divided 
into the anterior and posterior plexus. The former is de- 
rived from both of the semilunar ganglia, and from the 
right pneumogastric nerve ; the latter comes principally from 
the left semilunar ganglion. The left pneumogastric nerve 
sends filaments to join the plexus in the gastro-hepatic 
omentum. The hepatic plexus ramifies in the substance of 
the liver, accompanying the divisions of the hepatic artery 
and portal vein. It also gives off' secondary plexuses, which 
follow the branches of the hepatic artery to the pylorus, the 
convex border of the stomach, the pancreas, and the gall- 
bladder. They are named the pyloric^ the g astro-duodenal., 
the right gastro-epiploic^ the pancreatico-duodenal^ and the cystic 
plexuses. 

The SuPEl^iOR Mesenteric Artery, Fig. 15G (lo) and 
Fig. 159 (9), arises from the aorta just below the coeliac artery. 
Its origin is concealed by the pancreas, which should be 
turned upwards and fostcncd with hooks. It passes down- 
wards in front of the inferior transverse portion of the duo- 
denum to the commencement of the attached border of the 
mesentery, between the lamina3 of which it continues down 
to the junction of the small with the large intestine. In its 
course it forms a curve with the convexity to the left, and 



880 



OF THE ABDOMEN. 



the concavity to the right. It supplies the whole of the 
small intestine with the exception of the upper part of the 
duodenu.m, the caecum, the ascending, and about one-half of 
the transverse colon. Its branches are the following : — 

The pancreatico-duodenalis, Fig. 156 (is), is given off be- 
neath the pancreas. It sends twigs to the pancreas and the 
duodenum, and anastomoses with a branch of the same name 
from the hepatic artery. 

The branches to the small intestine^ Fig. 156 (le, le), are 

Fig. 156. 




The Course and Distribution of the Superior Mesenteric Artery. — 1. 
The descending portion of the duodenum. 2. The transverse portion. 3. The jeju- 
num. 4. Thelpancreas. 5. The ileum. 6. The csecum, from which thef appen- 
dix vermiformis is seen projecting. 7. The ascending colon. 8. The transverse 
colon. 9. The commencement of the descending colon. 10. The superior mesen- 
teric artery. 11. The colica media. 12. The branch which inosculates with the 
colica sinistra. 13. The branch of the superior mesenteric artery, which inosculates 
with the pancreatico-duodenalis. 14. The colica dextra. 15. The ileo-colica. 16, 
16. The branehes from the convexity of the superior mesenteric to the small in- 
testines. 



VESSELS AND NERVES OF ABDOMINAL VISCERA. 381 

from fifteen to twenty in nnmber. They arise from the- 
convexity of tlie artery, and after passing a short distance 
nearly parallel to each other, between the layers of the me- 
sentery, each one bifurcates. By the inosculation of these 
bifurcations with each other, a series of arches, or one con- 
tinuous arch, is formed, from the convexity of which another 
set of branches arise. These, much more numerous than 
those which arise directly from the artery, inosculate with 
each other, and form a second series of arches, from the con- 
vexity of which another set of branches arise and inosculate 
with each other. By the repetition of this process the third, 
fourth, and sometimes the fifth series of arches are formed 
by the time the middle portion of the small intestine is 
reached. Having reached the intestine, the last branches 
divide into two sets, which ramify on the opposite sides of 
the bowel ; some of them between the serous and muscular 
coats ; others perforate the muscular layer, and terminate in 
the mucous membrane. 

To dissect the arteries to the small intestine, the mesen- 
tery should be spread out and made tense. It is not neces- 
sary that the student should dissect all of them, in order to 
understand their general arrangement. 

The hranches to the large intestine arise from the concavity 
of the main trunk. There are three in number, the ilio- 
colic, the right colic, and the middle colic. They pass be- 
tween the layers of the meso-colon, and bifurcate to form a 
single series of arches, from which branches proceed to the 
large intestine, upon which they ramify in the same manner 
as the arteries do on the small intestine. 

The ileo-colic^ or inferior colic^ Fig. 156 (is), descends to 
the caecum to divide into branches, to be distributed to the 
lower part of the ileum, the ca3cura, the appendix vermi- 
formis cseci, and the lower part of the ascending colon. It 
sends a branch upwards to anastomose with the right colic. 

The right colic^ Fig. 156 (14), or, according to some, the 
middle colic^ goes horizontally to the ascending colon, and 
divides into an ascending and a descending branch, to anas- 
tomose, the one with the middle colic, and the other with 
the ileo-colic. 

The middle colic^ or the superior colic, Fig. 156 (11), pro- 
ceeds upwards to the right half of the colon, and like the 
preceding, divides into two branches. One of these anasto- 



882 



OF THE ABDOMEN. 



moses witli tlie ascending brancli of tlie right colic, and the 
other with the left colic branch of the inferior mesenteric 
artery. 

Fig 157. 




A View of the Portal System. — 1. The liver. 2. The stomach. 3. The 
spleen. 4. The pancreas. 5. A section of the duodenum. 6. The ascending colon. 
7. The small intestines. 8. The descending colon, a. The portal vein. h. The 
splenic vein. c. The right gastro-epiploic. d. The inferior mesenteric, e. The 
superior mesenteric. /. Section of the superior mesenteric artery. 

The SuPERioE Mesenteric Yein, Fig. 157 (e), corresponds 
to the artery just described, and originates in that portion 
of the intestine which is supplied by that artery. Its main 
trunk passes upwards over the inferior transverse portion of 
the duodenum, and beneath the pancreas where, in front of 
the aorta and to the left of the ascending vena cava, it unites 
with the splenic vein to form the vena porta3. Its branches 
are the same as those of the artery which it accompanies. 



VESSELS AND NERVES OF ABDOMINAL VISCERA. 883 

The Superior Mesenteric Plexus, Fig. 142 (le), pro- 
ceeds from the lower part of the solar plexus. The nervous 
cords in it are large and numerous, forming a sheath for the 
trunk of the artery. It divides into secondary plexuses, cor- 
responding to the divisions of the mesenteric artery. In the 
mesentery, the filaments are long, slender, and straight. Some 
of them unite to form arches just before they penetrate be- 
tween the coats of the intestine. This is the largest plexus 
in the body. 

The Inferior Mesenteric Artery, Fig. 155 (n), and 
158 (9), arises from the aorta, from one to two inches above 
its bifurcation into the common iliacs. It passes downwards 
along the aorta, and across the left common iliac, to enter the 
pelvis. It is much smaller than the superior mesenteric. It 
supplies the left portion of the transverse colon, the descend- 
ing colon, the sigmoid flexure, and the upper part of the 
rectum. In its course it sends off the following branches : — 

The left colic artery^ Fig. 158 (10), passes over the left 
kidney, between 'the layers of the meso-colon, to the de- 
scending colon. It divides into an ascending and descend- 
ing branch. The former anastomoses with the middle colic 
branch of the superior mesenteric, thus establishing a free 
anastomotic connection between the two mesenteric arteries ; 
the latter joins the sigmoid artery below. 

The sigmoid arteries^ Fig. 158 (12), proceed transversely 
to the sigmoid flexure, and divide into branches to anasto- 
mose above with the left colic, and below with the superior 
hemorrhoidal. 

The superior hertiorrhoidal artery^ Fig. 158 (13), passes to 
the upper part of the rectum, between the laminae of the 
meso -rectum. Its branches anastomose with the sigmoid 
above, and the middle hemorrhoidal below. 

The Inferior Mesenteric Vein, Fig. 153, c7, is formed by 
branches which correspond to those of the inferior mesenteric 
artery. A free anastomosis exists between the superior and 
middle hemorrhoidal veins. It passes upwards to empt}^ into 
the splenic vein behind the pancreas. Sonictimes it opens 
into the superior mesenteric vein. 

The Inferior Mesenteric Plexus, Fig. 112 (le), is de- 



884 



OF THE ABDOMEK. 



rived from tlie aortic plexus. It supplies tliat portion of tlie 
large intestine to wMcli the inferior mesenteric artery is dis- 
tributed. 




The Distribution and Branches of the Inferior Mesenteric Artery. — 1.1. 
The superior mesenteric artery, with its branches and the small intestines turned 
over to the right side. 2. The caecum and appendix cseci. 3. The ascending colon. 
4. The transverse colon raised upwards. 5. The descending colon. 6. Its sigmoid 
flexure. 7. The rectum. 8. The aorta. 9. The inferior mesenteric artery. 10, 
The colica sinistra, inosculating with 11, the colica media, a branch of the superior 
mesenteric artery. 12, 12. Sigmoid branches. 13. The superior hsemorrhoidal 
artery. 14. The pancreas. 15. The descending portion of the duodenum. 

The Spekmatic Aetekies, Fig. 159 (i o), usually arise a 
little below the renal, from the forepart of the aorta. Each 



VESSELS AND NEEVES OF ABDOMINAL VISCERA. 885 

descends on the side of the spine, and over the psoas magnus 
and iliacus internus muscles to the internal inguinal ring, 
where it joins the spermatic cord. They cross the ureters, 
and are accompanied by the spermatic veins. In the female, 
they go to the ovaries, and are called the ovarian arteries. 
There are sometimes two on the same side. The right one 
occasionally passes beneath the vena cava. They supply the 
testicles. 

The Spermatic Yeins in the abdomen accompany the 
spermatic arteries. The left one usually terminates in the 
renal, and the right one in the ascending vena cava. The 
latter passes beneath the right and lower portion of the 
mesentery, and the /ormer beneath the sigmoid meso-colon. 

The Spermatic Plexus accompanies the spermatic artery 
to the testicle. In the female, the corresponding plexus fol- 
lows the ovarian artery to the ovary and the uterus. It is 
derived from the renal plexus. 

The Eenal Arteries, Fig. 159 (7), sometimes called the 
emulgent arteries, arise from the aorta opposite to the kidneys. 
They are very large in. proportion to the size of the organs 
which they supply. The right one is longer than the left, 
and passes beneath the vena cava. The corresponding veins 
are usually situated in front of them. When the arteries reach 
the fissures of the kidneys, they divide into several branches. 
Sometimes, instead of one there will be two or three on the 
same side. They are also subject to considerable variation in 
their origin. 

The Eenal Yeins convey the venous blood from the 
kidneys to the ascending vena cava. The left is the longest, 
and passes over the aorta ; it also receives the left spermatic 
vein. The veins are in front of the corresponding arteries. 
They open into the vena cava at right angles. The supra- 
renal vein on the left side usually opens into the renal of the 
same side. 

The Eenal Plexus, Fig. 142 (14), is formed on each side 
by filaments from the solar plc;s:us and from the lesser 
splanchnic nerve. It accompanies the renal artcr}^ to the 
kidney. 

The Supra-Eenal Arteries, Fig. 159 (e), arise from the 
83 



386 



OF THE ABDOMEN, 



sides of the aorta, sometimes from the phrenic or renal. They 
supply the snpra-renal capsules and the surrounding adipose 
tissue. 

Fig. 159. 




The Abdominal Aorta with 
ITS Branches. — 1. The phrenic 
arteries. 2. The coeliac axis. 
3. The gastric artery. 4. The 
hepatic artery, dividing into 
the right and left hepatic 
branches. 5. The splenic ar- 
tery, passing outwards to the 
spleen. 6. The supra-renal ar- 
tery of the right side. 7. The 
right renal artery, which is 
longer than the left, passing 
outwards to the right kidney. 
8. The lumbar arteries. 9. The 
superior mesenteric artery. 10. 
The two spermatic arteries. 11. 
The inferior mesenteric artery. 
12. The sacra media. 13. The 
common iliacs, 14. The in- 
ternal iliac of the right side. 

15. The external iliac artery. 

16. The epigastric artery. 17. 
The circumflex ilii artery. 18. 
The femoral artery. 



The Supka-Eenal Veins open, the right into the vena 
cava, and the left into the renal vein. 



Dissection of the Viscera. 



The viscera which have been examined in situ^ can now be 
removed from the abdomen for the purpose of dissecting 
them, and studying their structure. The small intestine 
below the duodenum, and the large above the rectum, 



THE STOMACH. 



387 



should be removed first. To do this, apply two ligatures 
around the jejunum, at its commencement, and also two 
around the lower end of the sigmoid flexure of the colon, 
and divide the intestine between the ligatures at each place. 
To detach them will require a division of the mesentery, the 
meso-caecum, and the meso-colon, including the omentum 
majus. These may be laid aside until the stomach and duo- 
denum have been removed and examined. 

To remove the stomach, apply two ligatures to the duode- 
num, about an inch from the pylorus, and divide it between 
them; then apply a ligature to the oesophagus as it passes 
through the diaphragm, and divide it above the ligature. 
The spleen may be taken out with the stomach, or by 
itself. The pancreas and the remaining portion of the duo- 
denum should be removed together. In dissecting them out, 
care should be taken not to injure the aorta and vena cava. 

The stomach and the intestines should be emptied of their 
contents, and thoroughly cleansed before they are examined. 
This may be done by filling them repeatedly with water, or 
by allowing the water to flow through them from the stop- 
cock of a hydrant. 



The Stomach. 



To study the external appearance of the stomach it should 
be inflated. It has a 



conical form, being curv- 
ed upon itself. Its apex 
is cylindrical, and joins 
the duodenum, where 
there is a slight constric- 
tion. Its hase is rounded, 
and projects from two to 
three inches beyond the 
cardiac orifice. This por- 
tion has been desicrnated 
the great cnl-de-sac^ or 
great tuberosity, Fig. IGO, c, 
of the stomach. Near 
the pyloric extromit}^, 
and on the convex side, 



Fig. 160 




Diagram Outt-ine of Stomach. — a. Great 
curvature, h. Lesser curvature, e. Left end, 
great cul-de-sac or fundus, d. Small cul-de- 
sac or antrum pylori, o. (Esophageal oritice 
or cardia. q. Duodenal oritice or pylorus. 



388 OF THE ABDOMEN. 

is a dilatation called the small cul-de-sac^ Fig. 160, d. Instead of 
there being a constriction around the cardiac orifice, as there 
is around the p jloric, the oesophagus expands somewhat as it 
joins the walls of the stomach. 

The stomach is everywhere covered by peritoneum, except 
a narrow space along each of its borders where the laminae 
of the greater and lesser omenta are separated for the trans- 
mission of vessels and nerves. This space is diminished in 
size when the stomach is distended. 

Perhaps no organ in the body is subject to greater varia- 
tion in size than the stomach. This is owing, probably, in 
a great measure, to the habits of the individual in regard to 
eating. Its coats being very dilatable, yield to a distending 
force, which may be exerted by the introduction of large 
quantities of food into the stomach until it has acquired an 
enormous capacity. It is not unfrequently found very much 
contracted in the dead subject. It also varies considerably 
in its relative dimensions, being much longer and narrower 
in some cases than in others. 

The stomach has four different layers in its parietes. 
These differ from each other in structure and in function. 
In addition to these, it has bloodvessels, nerves, and lym- 
phatics. The layers are a mucous, a fibro-ceUular, a mus- 
cular, and a serous or peritoneal. 

The Sekous Coat, as has been seen, is a portion of the 
peritoneum. It furnishes to the stomach a perfectly smooth 
surface, which is constantly lubricated with a serous exhala- 
tion which prevents the occurrence of friction in its move- 
ments on contiguous surfaces. It also adds strength to its 
parietes, and, by its reflections, assists in keeping it in its 
place. 

The Muscular Coat consists of longitudinal, circular, 
and oblique fibres. To expose these, the serous layer should 
be removed while the stomach is distended with air. This 
is to be done partly by tearing and partly by dissecting it 
off. Frequently, when the stomach is inflated, the fibres can 
be very distinctly seen without any dissection. This is the 
case, especially when the muscular layer is strongly deve- 
loped. The muscular fibres of the stomach belong princi- 
pally to the non-striated or involuntary class. 



THE STOMACH. 



889 



The longitudinal fibres^ Fig. 161 (e), are placed next to the 
serous coat. If a portion of the oesophagus be inflated with 

Fig. 161. 




A Front View of the Stomach, distended by Air, with the Peritoneal 
Coat turned off. — 1. Anterior face of the oesophagus. 2. The cul-de-sac, or 
greater extremity. 3. The lesser or pyloric extremity. 4. The duodenum. 5, 6. 
A portion of the peritoneal coat turned back. 6. A portion of the longitudinal 
fibres of the muscular coat. 7. The circular fibres of the muscular coat. 8. The 
oblique muscular fibres, or muscle of Gavard. 9. A portion of the muscular coat 
of the duodenum, where its peritoneal coat has been removed. 

the stomach, they will be seen to be a continuation of the 
longitudinal fibres of that tube. They are most numerous 
along the concave border and near the pylorus, from which 
they are continued on to the small intestine. 

The circular fibres^ Fig. 161 (7), pass round the circum- 
ference of the stomach from the cardiac to the pyloric orifice. 
They increase in number towards the p3dorus. Around the 
pyloric orifice they are collected into a sphincter which is 
capable of closing that opening, so as to prevent the passage 
of the contents of the stomach into the duodenum during 
the time of its contraction. 

The oblique fibres, Fig. 161 (s), which are sometimes ab- 
sent or very indistinct, pass from one side of the stomach to 
the other around the great cul-de-sac to the left of the car- 
diac oiifice. 

The Fibro-Cellulak Coat is placed between the muscu- 

33^- 



390 



OF THE ABDOMEN. 



lar and mucous, to the former of wliich. it is closely con- 
nected by processes which are sent in between its fibres. 
The arteries and nerves, after passing through the muscular 
coat, ramify in this. By its density and intimate connection 
with the muscular layer, it contributes much to the strength 
of the walls of the stomach. It has been regarded by some 
as the framework of this organ. 

The Mucous Coat, Fig. 162, should be examined when 
the stomach is everted and inflated, and also when everted 
bu.t not distended. It glides freely on the fibro-cellular 
layer to which it is applied, and hence when the stomach is 
empty and contracted, it is thrown into numerous folds or 
Tugoe^ which disappear again when the organ is distended. 
The principal part of these folds have a longitudinal direction. 
There are, however, some which intersect these obliquely, 
and others transversely. 

At the cardiac orifice^ when the stomach is empty, the 
folds of the mucous membrane present a stellated appear- 



Fig. 162. 

A Vertical and Longi- 
tudinal Section op the 
Stomach and Duodenum, 
made in such a direction 
as to include the two 
Orifices op the Stomach. 
— 1. The cesophagus ; upon 
its internal surface the pli- 
cated arrangement of the cu- 
ticular epithelium is shown. 
2. The cardiac orifice of the 
stomach, around which the 
fringed border of the cuti- 
cular epithelium is seen. 3. 
The great end of the sto- 
mach. 4. Its lesser or pylo- 
ric end. 5. The lesser curve. 
6. The greater curve. 7. 
The dilatation at the lesser 
end of the stomach, which 
has received from Willis the 
name of antrum of the py- 
lorus. This may be regarded as the rudiment of a second stomach. 8. The rugse 
of the stomach, formed by the mucous membrane : their longitudinal direction is 
shown. 9. The pylorus. 3 0. The oblique portion of the duodenum. 11. The 
descending portion. 12. The pancreatic duct and the ductus communis choledo- 
chus close to their termination. 13. The papilla upon which the ducts open. 14. 
The transverse portion of the duodenum. 15. The commencement of the jejunum. 
In the interior of the duodenum and jejunum the valvulas conniyentes are seen. 




THE STOMACH. 391 

ancCj and wliere tlie mucous membrane of tlie oesopliagus 
joins that of the stomach, its epithelium exhibits a fringed or 
festooned border, Fig. 162 (2). There is no circular fold or 
sphincter muscle at this orifice as there is at the pyloric^ where 
the mucous membrane projects inwards from the circumfer- 
ence of the opening between the stomach and the duodenum, 
so as to form a partial septum between the cavities of these 
organs. With the aid of the circular fibres contained be- 
tween the laminae of this fold, it is capable of closing the 
orifice which it surrounds. If the stomach and duodenum 
be inflated and dried, a good view of this fold, with the cir- 
cular aperture in its centre, may be obtained. The laminaa 
of which it is composed resemble, in their organization, the 
one the gastric, the other the duodenal mucous membrane. 

The color of the mucous membrane of the stomach varies 
in health as well as in disease. In the very young, it has a 
bright reddish tint, while in the aged it usually presents a 
dark-grayish appearance. It is found of a brighter red if 
death has occurred when it was full and during the process 
of digestion than if when empty and free from vascular ex- 
citement. Its color is also frequently modified by the pre- 
sence of bile, or by the action of the gastric juices. 

The mucous membrane has not the same 
thickness and vascularity in every part of ^^^' ^^^' 

the stomach; being thicker towards the p^^^^^^^^^T^in^?^^ 
pyloric, and more vascular towards the 
cardiac orifice. There seems to be, also, 
some difference in susceptibility to disease 
in its right and left portions. 

Papillce may be observed with the aid 
of a lens on the mu.cous surface in all 
parts of the stomach. They are more oF^urMucws Mk'c- 
numerous, however, in the pyloric than brane ov the Human 
in the cardiac extremity. They arc sepa- Stomach, magnified 

.-IP 1 ,T < 7, -^ ^32 DIAMETERS. — AttOF 

rated Irom each other hj cells ^ or alveoli, Dr.SprottBoyd. Tho 

in which may be seen the iiioutlis of iiexagonai coils Avith 

small tubes. These tubes are lined by '^SdmarJinfal^Vu^ 

a columnar epithelium. They are sup- uuniths of tiie tubuu 

posed to secrete the gastric juices. aro'thown.''" ""^ ''''^' 

The vessels and nerves of the stomach 

were examined before it was removed from the abdomen. 



-i^"^~ ' .^^S^-yyj: 



392 



OF THE ABDOMEN. 



The Small Intestine. 




The small intestine is divided into three portions : the duo- 
denum^ the jejunum^ and the ileum. This division is wholly 
arbitrary, and practically is of little value. The small in- 
testine is about twenty feet in length. It diminishes in size, 
and in the thickness of its coats, from its commencement to 
its termination. Its structure is similar to that of the stomach, 
being composed of a serous, a muscular, a cellular, and a 
mucous coat. 

The Seeous Coat consists principally of a single dupli- 

cature of the peritoneum, be- 
Fig. 164. tween the laminae of which 

the vessels and nerves reach 
the intestine along its con- 
cave or attached border. 
The duodenal portion of the 
intestine is not entirely in- 
vested with a serous layer, 
as was observed in the ex- 
amination of it in situ. 

The MuscuLAE Layee, 
Fig. 164, is composed of a 
longitudinal and a circvdar 
set of fibres. The action of 
the bowel in propelling for- 
ward its contents, depends mainly on the circular fibres, which 
are much more numerous than the longitudinal. They do 
not, all of them at least, extend entirely around the circum- 
ference of the intestine. To obtain a good view of the longi- 
tudinal fibres, a section of the intestine should be inflated, 
and the peritoneum carefully dissected or peeled off. They 
will be found more numerous on the convex than on the con- 
cave border of the bowel. 

The Cellulae Layee is interposed between the mus- 
cular and mucous layers, between which it forms a bond of 
union, allows the latter to glide freely on the former, and 
furnishes a medium for the transmission and subdivision of 
the vessels and nerves supplied to the mucous membrane. 



a View of the Muscular Coat of the 
Ileum. — ?, 1. The peritoneal coat. 2. A 
portion of this coat turned off and show- 
ing a portion of the longitudinal fibres of 
the muscular coat adherent to it. 3, 4, 5. 
The circular muscular fibres in different 
parts of the intestine. 



THE SMALL INTESTINE. 393 

This layer can be very satisfactorily demonstrated by evert- 
ing a portion of the intestine and then forcibly distending it 
with air. The preparation should be dried, and the mncous 
membrane afterwards removed. 

The Mucous Membeane of the small intestine should be 
carefully observed by the student. He should become per- 
fectly familiar with the appearance of it as seen in the dis- 
secting room, where he will have an opportunity of examining 
it in a healthy as well as in a diseased condition. The follow- 
ing should be particularly noticed: The valvulae conniventes, 
the common orifice of the pancreatic and biliary ducts, the 
villi, the glands of Lieberkiihn, Brunner, Peyer, and the 
glandulas solitariae. 

The Valvule Conniventes, Fig. 162 (is), are perma- 
nent, crescentic folds of the mucous membrane, extending 
from one-half to two-thirds around the circumference of the 
intestine. They are most prominent in the lower part of the 
duodenum and in the jejunum, while in the upper part of the 
duodenum and in the lower part of the ileum they are usu- 
ally absent. They increase the extent of mucous surface, and 
also serve to retard the passage of the food through the in- 
testine. 

The Orifice of the ductus choledochus communis^ and the 
pancreatic duct^ Fig. 162 (is), is situated on the summit of a 
small eminence at the lower part of the descending portion 
of the duodenum, and about three inches and a half from the 
pylorus. It is readily observed when the duodenum is everted, 
or when a probe is carried through the biliary duct. These 
ducts sometimes open into the intestine separately. The 
biliary duct is slightly constricted near its orifice. After 
perforating the muscular coat, the two ducts run half an inch 
or more between it and the mucous membrane, before open- 
ing into the duodenum. When the intestine is inflated, air 
will not pass into these ducts on account of the mucous mem- 
brane being pressed against the muscular layer. 

The Villi, Fig. 165, are small vascular eminences, which 
are found on the mucous surface of the whole of the small 
intestine. They vary from one-fifth to four-fifths of a lino in 
length. They arc most numerous in the duodenum and jeju- 
num where the valvuh\3 conniventes arc most prominent. 



394 OF THE ABDOMEN. 

Some of tliem have a conical form, while others have a 
flattened or triangular shape. Thej give to the internal 
surface of the intestine a velvety appearance. They consist 
of projections of the mucous membrane, covered by epithe- 
lium, and contain a network of capillary vessels, and lacteals 
or absorbent vessels. They are very distinctly seen, when a 
portion of the intestine is minutely injected and allowed to 
float in water or alcohol. 

The Glands, or Follicles of Lieberkuhn, are small 
crypts found in every part of the small intestine. They are 
situated between the villi and around the larger glands. They 
are similar to the small tubuli observed in the mucous mem- 
brane of the stomach. 

The Glands of Brunner are small glandular bodies, 
situated in the cellular coat of the duodenum, forming small 
projections on the surface of the mucous membrane. They 
are about the size of hemp seed. Each gland is composed of 
several lobules, which open on the mucous surface through, a 
common duct. In structure they resemble the salivary glands. 

The GLANDULiE SoLiTARi^, Fig. 165, are small projecting 
bodies, observed along the whole track of 
the small intestine. They are covered 
by villi, and surrounded by the crypts of 
Lieberkuhn. They have no excretory 
ducts, or open mouths. When they are 
cut into they are found to contain a 
whitish, granular substance. Their use 
is not known. 



The Glands of Peyer, Fig. 166, or 
Solitary Gland of the glandulce agminatce^ are observed 
THE Small Intestixe ppincipally in the lower portion of the 

MAGNIFIED. (Boehm.) f; ^ i 1 • ^ -. J. J.^ 

The surface is beset with llcum, and OU the Side OppOSltC tO tilC 

villi: the mouths of nu- attachment of the mesentery. They con- 

merous crypts of Lieber- • , r> , i • • ^ n 

kuhn are also seen. sist of patches varymg m number irom 

ten to thirty, or more, of an oval or ob- 
long shape, being from one to two or three inches in length, 
and half an inch in breadth. They have no excretory ducts. 
Each patch is supposed to be an aggregation of the solitary 
glands, and, like them, their function has not been ascer- 
tained. To examine them, the intestine should be laid open 




THE LAEGE INTESTINE. 



895 



Fig. 166. 



Enlarged View of a part of 
A Patch of Peter's Glands. 
It shows the different forms of the 
individual vesicles, the zone of 
foramina belonging to Lieber- 
kiibn's follicles around each, the 
mouths of other of those follicles 
and numerous villi situated be- 
tween the vesicles, not upon them, 
and, lastly, the surrounding dark- 
er part of the mucous membrane 
beset merely with villi and fol- 
licles. 




along its concave or attadaed border, and the mucus being 
carefully washed off, should then be held before a strong light. 

The Laege Intestine. 



The location and the relations of the large intestine, except 
the rectal portion, have been described. Its caliber is much 
larger than that of the small intestine. It is largest at its 
commencement, and gradually diminishes in size to the lower 
part of the rectum, where, just above the anus, a pouch or 
dilatation exists. The external appearance of the large is 
quite different from that of the small intestine. Instead of 
being smooth and cylindrical, it presents, except the rectum, 
a sacculated appearance, the pouches being arranged longitu- 
dinally in three series, and separated by the same number 
of smooth surfaces extending the whole length of the ca.^cum 
and colon. 

To dissect the large intestine, it should be removed, as 
before mentioned, from the abdomen and inflated. As the 
rectum cannot be examined until the soft parts of the pelvis 
are dissected, it will be necessary to apply a ligature to the 
upper part of the rectum, and divide the intestine just above 
it. A small portion of the ileum should be removed Avith 
the caecum and colon. 

With the exception of the lower part of the rectum, the 
large intestine has the same number of layers in its parictes 
as the small. 



896 



OF THE ABDOMEN. 



A part of the transverse colon is placed between the two 
ascending layers of the omentum majus, and it consequently 
has, like the stomach, two non-peritoneal surfaces. The peri- 
toneum on the csecum and colon presents numerous small 
pouches filled with fat. The length of these is diminished when 
the bowel is inflated. They are called appendices epiploicoe. 

The lo7igitudinal muscular fibres in the caecum and colon 
are collected into three hands, which correspond to the smooth 
surfaces between the pouches. They commence at the ap- 
pendix vermiformis cseci, and terminate at the rectum. The 
sacculated form of the large intestine is caused by the rela- 
tive shortness of these bands. The circular fibres are most 
numerous in the ridges which project into the intestine be- 
tween the sacculi. 

The cellular coat requires no special notice. It separates 

the mucous from the muscular 
coat in the same manner as 
the corresponding la.yer does 
in the small intestine. 

The mucous coat has a pale 
appearance. It has no folds 
corresponding to the valvulse 
conniventes in the small in- 
testine. The projections be- 
tAveen the sacculi are formed 
of all the layers except the 
longitudinal fibres of the 
muscular coat. It has very 
few if any villi. It has alveoli 
similar to those observed in 
the stomach. It is every- 
where thickly studded with 
the orifices of follicles or tu- 
bull, which resemble those 
of Lieberkiihn in the small 
intestine. There are also 
..tZT. ZT^lTl^ZS'^-r. fo^nd scattered oyer its sur- 

The end of the ileum. 2. Appendix faCC, CryptS Or folllcleS, of a 
Yermiforniis. 3. The caecum, or caput j • ^}^qqq COUSist of 
coll. 4. The transverse colon. 5. The & . ^ 
descending colon. 6. The sigmoid flex- Small pOUChcS With Contract- 
ure. 7. Commencement of rectum. 8,8. q^ orificCS, Opening OUthc 
The rectum. 9. The anus. The levator o mi 
ani muscle is seen ou each side. muCOUS SUrtaCC. Incy are 




THE LARGE INTESTINE. 



397 



more numerous in tlie csecum and appendix vermiformis than 
elsewhere. These follicles may be inflamed without involv- 
ing other parts of the mucous membrane. 

The Appendix Yermiformis C^ci, Fig. 168 (5), has the 
same number of layers in its walls as the intestine. It opens 
into the caecum by an orifice about the size of a goose-quill. 
Sometimes a valvular fold of mucous membrane is found 
situated at this opening. Foreign bodies sometimes pass into 
it, and give rise to inflammation and ulceration of its coats. 
It is not known to have any function. 

The Ileo-C^CAL Yalve, Fig. 168 (3), or the valve of Bau- 
hin^ is placed at the opening of the small into the large intes- 
tine. It consists of two folds of the mucous membrane, in- 



cluding areolar tissue and a layer 
of muscular fibres. The upper 
fold is sometimes called the ileo- 
colic valve. They project into the 
large intestine so as to form a 
slit between their free borders. 
This slit is placed transversely 
to the large intestine between the 
caecum and colon, and looks more 
into the latter than into the for- 
mer. A fold of mucous mem- 
brane is extended from each 
commissure for some distance on 
the inner surface of the intestine ; 
they have been named the/rcena 
of the valve. The lower fold, or 
ileo-ccecoJ valve^ is somewhat larger 
than the ileo-colic. The shape of 
the aperture between the valves 
depend very much on the man- 
ner in which the peritoneum is 
reflected from the small to the 
large intestine. 

The mucous membrane of the 

ileum is continued to the free 

borders of the valves where that 

of the ca3cum and colon com- 

34 



Fig. 168. 




A ViKW OF THE C-ECUM — AFTER 
IT HAS BEEN DISTEXPKP — DRIED 

AND TvAin OPEN IN Front. — 1. The 
ascending colon. 2. Ono of tbo 
cells of tiie colon. 3. The ileo-can^al 
valve. 4. Tho opening into tho 
appendix vermiformis ctvci. 5. Ap- 
pendix vermiformis ea^ci. 6. A sec- 
tion of tho lower cud of the ileum. 



398 OF THE ABDOMEN. 

mences. In this respect these valves resemble the one be- 
tween the stomach and duodenum. When these valves are 
closed the contents of the large intestine cannot pass into 
the small. 

To obtain a good view of these valves and the opening 
between them, the student should inflate and dry the caecum 
and a portion of the colon and ileum, and then cut away a 
part of the former. 



The Dissection of the Liver. 

To dissect and study the liver, it should be removed from 
the abdomen. To do this it will be necessary to divide the 
ligaments or folds of peritoneum which attach this organ 
to the diaphragm, and also to remove a portion of the ascend- 
ing vena cava with it. Care should be observed not to in- 
jure the diaphragm in this dissection. 

The liver presents, for examination, an upper anterior, 
and an inferior posterior surface, a posterior and an anterior 
border, and a right and left extremity. 

It is the largest gland in the body. Its weight varies from 
two to five pounds. Both its weight and size, however, will 
depend much on the amount of blood contained in its vessels. 
Its size is also greatly modified by disease. In some instances 
it has been found to weigh from twenty-five ta thirty pounds, 
while in others its weight did not exceed a pound. It has a 
reddish brown color ; but in this respect it varies very much 
in different subjects, and especially when diseased. It is # 
fragile, and easily broken when pressed between the thumb 
and finger. Owing to its brittleness, it is liable to be lacerated 
by blows inflicted on the abdomen. 

The U2^per anterior surface of the liver is convex, and 
moulded to the concavity of the diaphragm. The attach- 
ment of the suspensory ligament divides it into a right and 
left surface, corresponding to the right and left lobes. 

The posterior horder is rounded, thick at its right, and thin 
at its left extremity. The anterior horder is thin, presenting 
quite a sharp edge. The right extremity is thick behind and 
thin anteriorly. The left extremity is thin. It will be ob- 
served that the posterior and right portion of the liver is the 
thickest part of it. 



DISSECTION OF THE LIVER. 



899 



The inferior posterior surface^ Fig. 169, is irregularly con- 
cave. It presents, nsuallj, indentations for the right kid- 
ney, the colon, and the stomach. It has three fissures ; two 
of which extend from the anterior to the posterior border. 
These last are named the right and left antero-posterior fissures. 
The left antero-posterior is sometimes called the longitudinal 
fissure^ Fig. 169 (s). It indicates the line of division between 
the right and left lobes of the liver on its under surface. 
The remaining one connects these two, and is called the trans- 
verse fissure^ Fig. 169 (15). The antero-posterior fissures are 
separated anteriorly by the lohus quadratus^ Fig. 169 (24), and 
posteriorly by the lolus Spigelii^ Fig. 169 (25), while the 
lobes themselves are separated from each other by the trans- 
verse fissure. The right antero-posterior fissure is interrupted 
just behind the transverse fissure, by a process extending 
from the lobus Spigelii to the under surface of the right 
lobe; this process is called the lohus caudatus^ Fig. 169 (26). 

The right antero-posterior fissure is occupied anteriorly 
by the gall-hladder^ and posteriorly by the vena cava. The 
left antero-posterior fissure contains, anteriorly, the remains 



Fig. 169. 

The Inferior or Con- 
cave Surface of the Li- 
ver, SHOWING ITS Subdi- 
visions INTO Lobes. — 1. 
Centre of the right lobe. 

2. Centre of the left lobe. 

3. Its anterior, inferior, or 
thin margin. 4, Its poste- 
rior, thick, or diaphragma- 
tic portion. 5. The right 
extremity. 6. The left ex- 
tremity. 7. The notch on 
the anterior margin. 8, 
The umbilical or longitudi- 
nal fipsure. y. The round 
ligament or remains of the 
umbilical vein. 10. The 
portion of the suspensory li- 
gament in connection with the round ligament 11. Pons hcpatis, or band of liver 
across the umbilical fissure. 12. Posterior end of longitudinal fissure. 13, U. 
Attachment of the obliterated ductus venosus to the aseonding vena cava. 15. 
Transverse fissure. IG. Section of the hepatic duct. 17. Hepatic artery. IS. Its 
branches. 19. Vena portai. 20. Its sinus, or division into right and left branches. 
21. Fibrous remains of the ductus vcnosus. 22. Call-bladder. 2.S. Its nock. 24. 
Lobus quadratus. 25. Lobus Spigelii. 26. Lobus caudatus. 27. Inferior vena 
cava. 28. Curvature of liver to tit the ascending colon. 20. Depression to fit the 
right kidney. 30, Posterior portion of its right concave surface ovor the re- 
nal capsule. 31. Portion of liver uncovered by tlie peritoneum. 32. Inferior edge 
of the coronary ligament in the liver. 33. Depression made by the vertebral 
column. 




400 



OF THE ABDOMEN. 



of the umhilical vein of the foetus, and posteriorly, the remains 
of the ductus venosus. The transverse fissure is occupied by 
the capsule of Glisson, the portal vein^ the hepatic artery and 
duct^ the hepatic plexus of nerves^ and the deep ahsorheni 
vessels. 

The pons hepatis^ Fig. 169 (i i), when present, consists of a 
portion of the substance of the liver, extending across the 
left antero-posterior fissure beneath the ligamentum teres. 

The mouths of the hepatic veins will be observed opening 
into the vena cava behind the lobus Spigelii, on the pos- 
terior border of the liver. There are usually three or four 
of these veins. 

The capsule of Glisson is a dense areolar tissue which sur- 
rounds the vessels in the transverse fissure, and is prolonged 
into the substance of the liver, forming sheaths, named portal 
canals, Fig. 170, a, a, for these vessels; it also forms the 
proper capsule of the entire organ, as well as an investment 




Section of a Portal Canal 
AND Portal Vein lying in it, in 
company with the Hepatic Ar- 
tery AND Duct. — P. Branch of ve- 
na portse, situated in a, a, a portal 
canal, formed amongst the lobules 
of the liver. The large orifices 
opening into the portal vein are 
the mouths of the vaginal branches. 
h. Orifices of interlobular veins, 
arising at once from the large vein. 
A. Hepatic artery. D. Hepatic 
duct. 



for its lobules or acini. The inner surface of the portal 
canals is connected to the vessels by loose areolar tissue, 
while the external surface is closely connected to the sub- 



DISSECTION OF THE LIVEE. 



401 



stance of tlie liver bj numerous prolongations sent off be- 
tween the lobules. 

The student should trace the portal vein, the hepatic artery 
and duct, or, at least, their principal divisions, in the substance 
of the liver ; also the hepatic veins. 

The vena portce enters the transverse fissure of the liver 
and divides into a right and left branch, forming at this di- 
vision the portal sinus. The branches enter the liver, and 
divide and subdivide until every part of the organ is reached. 
The subdivisions of it are named, the vaginal^ the interlobular^ 
and the lobular. 

The hepatic artery enters the liver with the vena portse, 
and divides into the same number of branches as it. Its 
subdivisions are named the vaginal^ the interlobular^ and the 
lobular. 

The hepatic duct accompanies the vein and artery in its 

Fig. 171. 



H. Longitudinal section of 
an hepatic vein. a, a. Por- 
tions of the canal from which 
the vein has been removed. 
h, b. Orifices of intralobular 
veins. The large orifices open- 
ing into the hepatic vein are 
the mouths of the sublobular 
veins. 




minute divisions, which have the same names. The spaces 
occupied by the portal vein, artery, and duct, are called the 
portal canals. 

34-^ 



402 OF THE ABDOMEN. 

The heimtic veins ^ Eig. 171, H, commence in tlie lobules by 
the intralobular veins ^ which end in the sublohular^ and these 
again terminate in the hepatic veins, of which there are, 
commonly, three or four principal trunks. These open into 
the vena cava near the diaphragm. They are not surrounded 
by areolar tissue like the portal vein, but adhere closely to 
the canals, the walls of which are very thin, and conse- 
quently do not collapse when they are divided. 

A branch of an hepatic vein is readily distinguished from 
one of the portal vein; as the latter is always accompanied 
by a branch of the hepatic artery and duct, is surrounded 
by areolar tissue, collapses when divided, and is - directed 
towards the transverse fissure. Neither the portal nor the 
hepatic veins have any valves. 

The nerves and the deep lymfpliatics of the liver accompany 
the divisions of the hepatic artery and portal vein. 

The proper substance of the liver consists of small granu- 
lar polyhedral bodies named lobules. Each one is about the 
size of a millet seed, and represents, in miniature form, the 
entire liver. It is invested by a process from the capsule of 
Glisson, except at its base, where it rests on a sublobular 
vein. 

Dissection of the G-all-Bladdee. 

The gall-bladder, Fig. 169 {22), and Fig. 172, is attached to 
the under surface of the right IoIdc of the liver, and occupies 
the anterior portion of the right antero-posterior fissure. It 
is of a conical form. The base is directed downwards, for- 
wards and to the right ; sometimes it projects beyond the 
anterior border of the liver, and again does not extend to it. 
The apex is directed backwards, upwards, and to the left, 
where it ends in the cystic duct. It is subject to much vari- 
ation in size. 

Its free surface is covered by peritoneum, which is leflected 
from it to the liver. Its adherent surface is in contact with 
the substance of the liver, from which it is easily separated 
after the peritoneum has iDeen divided around it. It has a 
fibro-cellular coat, which in some of the larger animals con- 
tains non-striated muscular fibres. The mucous membrane 
presents a honey -combed or reticulated appearance. It is 
stained with bile after death. 



DISSECTION" OF THE GALL-BLADDER. 



403 



The neck of the gall-bladder is doubled twice upon itself. 
This is caused principally by the manner in which the peri- 
toneum is attached to it. On the inside of the neck, Fig. 172 

Fig. 172. 



Shows the Three Coats 
OF the Gall-Bladder se- 
parated FROM each OTHER. 
— 1. The external or perito- 
neal coat. 2, 2. The cellular 
coat with its vessels injected. 
3, 3. The mucous coat co- 
vered with wrinkles. 4, 4. 
Valves formed by this coat 
in the neck of the gall-blad- 
der. 5, 5. Orifices of the 
mucous follicles at this point. 




(4, 4), the coats project inwards so as to form two or three 
folds, which resemble valves. They do not, however, inter- 
fere with the passage of the bile in either direction. 

The mjstic duct^ Fig. 173,/, is about an inch and a half in 
length. It unites with the hepatic duct to form the ductus 
choledochus communis. Its inner surface presents from ten 
to fifteen semilunar projections, which not unfrequently have 
a spiral form, resembling the thread of a screw. 

The Jiepatic duct^ Fig. 173,/, is formed by the union of two 
trunks in the transverse fissure of the liver. It is about an 
inch and a half in length. 

The ductus cJioledochus^ Fig. 173,/ is formed by the cystic 
and the hepatic ducts. It is about two inches and a half 
loDg. It is lined by a mucous membrane, Avhich is continu- 
ous on the one hand with the mucous membrane of the 
duodenum, and on the other with that of the cystic duct 
and the gall-bladder, and that of the hepatic duct and its 
numerous subdivisions in the liver. The fibrous layer of 
these ducts is regarded by some as being composed of the 



404 



OF THE ABDOMEN. 



non-striated muscular tissue. These ducts are partly covered 
by peritoneum. 

The gall-bladder is supplied with blood by the cystic 
branch of the hepatic artery, Fig. 155, h^ and with nerves 
by offshoots from the hepatic plexus. 



Dissection of the Panceeas. 

The pancreas, Fig. 173 {h^ t, ^), is analogous to the salivary 
glands. It is from six to seven inches in length, and about 
three-fourths of an inch thick. Its breadth varies, its right 
extremity or the head being much broader than its left, which 
is called the tail It has no proper fibrous capsule. In 
structure, it is similar to the parotid gland. It is composed 
of lobules, which are connected together by areolar tissue. 

The pancreatic duct. Fig. 173 (e), extends the whole length 

Fig. 173. 




In this figure, which is altered from Tiedemann, the liver and stomach are turned 
up, to show the duodenum, the pancreas, and the spleen. L The under surface of 
the liver, g. Gall-bladder. /. The common bile-duct, formed by the union of a 
duct from the gall-bladder, called the cystic duct, and of the hepatic duct coming 
from the liver, o. The cardiac end of the stomach, where the oesophagus enters. 
8. Under surface of the stomach, p. Pyloric end of stomach, d. Duodenum, h. 
Head of pancreas; t, tail; and i, body 'of that gland. The substance of the pan- 
creas is removed in front, to show the pancreatic duct (e) and its branches, r. The 
spleen, v. The hilum, at which the bloodvessels enter, c, c. Crura of diaphragm. 
n. Superior mesenteric artery, a. Aorta. 



DISSECTION OF THE SPLEEK. 405 

of the pancreas. It has a very white appearance when ex- 
posed in the substance of the gland. Its parietes are thin like 
those of the excretory duct of the submaxillary gland. The 
branches by which it is formed join it nearly at right angles. 
It is situated a little nearer to the anterior than to the poste- 
rior surface of the pancreas, and nearer to the lower than to 
the upper border. Unlike other excretory ducts, it terminates 
almost immediately after leaving the gland. Sometimes 
there are two ducts, which may or may not open separately 
into the duodenum. 

The lesser pancreas is merely the lower portion of the head. 
"When there are two ducts, it is in this part of the gland that 
the second one is found. 

The vessels and nerves of the pancreas have been described 
with the gland in situ. 



Dissection of the Spleen. 

The spleen, Fig. 173, r, occupies the deep part of the left 
hypochondrium. It has an oval form, being flattened and 
somewhat excavated on its inner side. It varies greatly in size. 
It has a deep red or purple color, especially when cut into. 
Its structure possesses but little firmness, and is easily broken 
up by pressure. It may be lacerated by blows on the exter- 
nal surface of the left hypochondriac region. 

It presents a convex surface which looks towards the dia- 
phragm and lower ribs, and a flat, slightly concave one, which 
is in apposition with the left extremity of the stomach. Its 
upper extremity is larger and more rounded than the infe- 
rior, and its posterior border is thicker than the anterior. 

A fissure^ or hilum, Fig. 173, z;, is observed on its flat sur- 
face, being nearer to the posterior than to the anterior bor- 
der. This fissure is occupied by the vessels and nerves of 
the gland. 

The spleen has, besides the peritoneal, a 2'>ropcr fihrous co- 
vering^ which not only invests the entire organ, but sends pro- 
longations into every part of it, which, by interlacing, form 
a perfect network. It is also reflected in from the hilum 
around the vessels so as to form for them sheaths. It is 
elastic, quite strong, and may be said to form the framework 
of the organ. The cellular arrangement formed by this struc- 



406 OF THE ABDOMEN. 

ture may be very well seen in a section of the spleen after 
repeatedly washing and squeezing it until the red pulpy 
substance, contained in the cells or interstices, has been re- 
moved. It will be observed that the processes sent in from 
the internal surface of the capsule are connected to the ex- 
ternal surface of the sheaths of the vessels. The peritoneum 
adheres closely to the fibrous capsule. 

The interstices are filled with a red pulpy granular sub- 
stance. This, when exposed to the air, assumes a bright red 
color. Small vesicular bodies have been noticed in the 
granular substance. 

The spleen is an exceedingly vascular organ, and its size 
depends much on the quantity of blood which it contains. 
It has no excretory duct. Sometimes one or more small 
bodies are found in the neighborhood of the spleen, which 
resemble it in color and structure. 



Dissection of the Kidneys. 

These are two organs for the secretion of the urine, situated, 
one in each lumbar region, Fig. 177 (i, i). They are some- 
times connected across the spine so as to form what is called 
the horse-slioe kidney. Sometimes one is entirely absent. 
They are usually smaller in the female than in the male. 
They are about four inches in length, two in breadth, and 
one in thickness. In shape they resemble the kidney bean. 
Their color is a deep brown-red. 

Each kidney, Fig. 174, presents an anterior and posterior 
surface, an upper and a lower extremity, and an outer and 
inner border. The anterior surface is more convex than the 
posterior, and the upper extremity is broader and thicker 
than the lower. The external border is convex, while the 
internal is concave and marked by quite a deep fissure or 
hilum, which contains the renal vessels, nerves, and excretory 
duct. The excretory duct is usually situated in the lower 
and posterior part of the fissure or hilum, while the veins 
are placed in the front part, with the arteries immediately 
behind them. 

The kidney has sl projoer fibrous capsule Avhich invests the 
entire organ, and sends into its substance fine delicate pro- 



DISSECTION" OF THE KIDNEYS. 



407 



Fig. 174. 




cesses wbicTi are easily broken. It also joins the fibrons 
layer of the ureter, and is prolonged internally along with 
the vessels, as far as the apices or 
pajnllce. It requires but little force 
to detach this membrane from the 
substance of the kidney. 

In dissecting the kidney, the student 
should, in the first place, carefully re- 
move the areolar tissue and fat from 
the hilum, so as to obtain a distinct 
view of the vessels and the ureter, 
Fig. 174 (7, 8, 11). Having done 
this, the ureter should be slit up on 
one side, cutting away at the same 
time a portion of the kidney. That 
part of the ureter situated in the hilum 
is named hs pelvis, Fig. 175 (e). There 
will be observed opening into the 
pelvis three apertures, sometimes only 
two ; these are called the infundihula^ 
Fig. 175 (5, 5, 5). If one of these now 
be laid open, a cavity will be seen 
with several eminences or papillce 
projecting into it. The cup-shaped 
depression which is observed sur- 
rounding each papilla is called the 
calix. Sometimes two papillae are 
found projecting into a single calix. 
Small openings may be noticed on 
each papilla, which are the mouths of 
uriniferous tubes, and if the kidney 
be pressed between the thumb and 
finger, urine may frequently be seen escaping from them. 

Each papilla is the apex of a comcal-shaped portion^ Fig. 
175 (3, 3) of the kidney, which is composed of a groat num- 
ber of straight tubes. If the kidney be divided through one 
of the apices, the outlines of the cone to which the apex 
belongs Avill be distinctly seen, having a striated appearance, 
with its base imbedded in a ditferent kind of structure. The 
Z^ase of each cone is rounded off, and reaches toAvithin about two 
lines of the external surface of the kidney. There are from 



A TiEW OF THE Right Kid- 
ney AND ITS Supra-Renal 
Capsule. — 1. Anterior face 
of the kidney. 2. External 
or convex edge. 3. Its inter- 
nal edge. 4. Hilum. 5. In- 
ferior extremity of the kid- 
ney. 6. Pelvis of the ureter. 
7. Ureter. 8, 9. Superior and 
inferior branches of the emul- 
gent artery. 10, 11, 12. The 
three branches of the emul- 
gent vein. 13. Supra-renal 
capsule. 14. Its superior 
edge. 15. Its external edge. 

16. Its internal extremity. 

17. The fissure on the ante- 
rior face of the capsule. 



408 



OF THE ABDOMEN. 



Fig. 175. 




ten to eighteen of tTiese cones, forming about one-fonrtTi part 
of the kidney. Eacli one is separate and distinct from the 
rest. They constitute what is called the medullary portions, 
while the remaining three-fourths is 
named the cortical or vascular sub- 
stance, Fig. 175 (2). The urine is 
secreted in the latter, which is much 
more vascular than the former, as it 
requires blood not only for nourish- 
ment but to supply the elements of 
which the urine is formed. It is less 
firm and more easily broken up than 
the medullary substance, and is 
usually of a brighter red color. 

When the two substances are ex- 
amined with the microscope, they are 
both found to contain tubes. These 
commence, for the most part, by 
closed but dilated extremities in the 
cortical substance. They are at first 
very tortuous, but as they proceed to 
enter the base of a cone, they assume a 
straight direction. They are known 
in the cortical substance as the con- 
voluted tubes of Ferrein^ and in the 
cones as the straight tubes ^ or the ducts 
of Bellini. From the extent of sur- 
face on the base of each cone, it will 
readily be seen that the number of 
tubes which enter it must be very 
great, and, also, that the number, by 
the union which is constantly taking 
place, must be greatly diminished 
before they reach the apex of the cone. The tubes which 
converge to form by their junction one of the straight tubes, 
constitute a pyramid of Ferrein. 

The corpuscles of Malpighi^ in the cortical substance, consist of 
tufts of vessels contained in the dilated extremities, and in cap- 
sular dilatations on the sides of the tubes of Ferrein. Each cap- 
sule is perforated by an afferent and an efferent vessel. The for- 
mer is an artery, and the latter a vein. After the vein leaves the 



a section of the kidney, 
surmounted by the supra- 
Benal Capsule ,• the swel- 
lings ON THE SURFACE JIARK 
THE ORIGINAL CONSTITUTION 

OF THE Organ of Distinct 
Lobes. — 1. The supra-renal 
capsule. 2. The vascular or 
cortical portion of the kidney. 
3, 3. Its tubular portion, con- 
sisting of cones. 4, 4. Two 
of the papillse projecting into 
their corresponding calices. 
5, 5, 5. The three infundibula; 
tlie middle 5 is situated in the 
mouth of a calyx. 6. The 
pelvis. 7. The ureter. 



DISSECTION OF SUPKA-EENAL CAPSULE. 



409 



Fig. 176. 




capsule it forms a plexus around the tube, and tlien termi- 
nates in a branch of the renal vein. 

The Uretees convey the urine from the kidneys to the 
bladder. They are from sixteen to eighteen inches in length. 
Below its pelvis each one is about 
the size of a goose-quill. The man- 
ner in which it is formed in the 
hilum by the calices, the infundibula, 
and the pelvis, has been noticed in 
the dissection of the kidney. Its walls 
consist of two layers, a fibrous and a 
mucous. The fibrous layer is said to 
contain muscular fibres, and is very 
dilatable. The mucous membrane 
is continuous above with the lining 
membrane of the urinifarous tubes, 
and below with that of the bladder. 
The manner in which the ureter per- 
forates the coats of the bladder will 
be noticed in the dissection of that 
organ. 

The Supea-Renal Capsule, Fig. 
175 (i), is a small body of a crescen- 
tic form, situated on the upper end 
of each kidney. The one on the 
right side is placed between the kid- 
ney and the liver, resting on the dia- 
phragm, and having the vena cava 
and the duodenum in front of it. 
The left one also rests on the dia- 
phragm, and has the spleen and pan- 
creas above and in front of it. 
They are moulded on the upper 

extremities of the kidneys, to which they are attached by 
loose areolar tissue. Without some care they might be 
readily confounded with the ftit which surrounds them. 

They are yellowish externally, and when cut into pre- 
sent a striated lamina or cortical substance of the same 
color, and a dark-colored medullary substance, of a much 
softer consistence. Occasionally they arc found to contain a 
small cavity iu the centre. Thcv bave no excretorv ducts, 
35 ■ 



Plan of the Renal Circu- 
lation; COPIED FROM Mr. 
Bowman's Paper. — a. A 
branch of the renal artery- 
giving off several Malpighian 
twigs. 1. An afferent twig to 
the capillary tuft contained in 
the Malpighian body, m; from 
the Malpighian body the uri- 
niferous tube is seen taking 
its tortuous course to t. 2, 2. 
Efferent veins; that which 
proceeds from the Malpighian 
body is seen to be smaller 
than the corresponding artery. 
p, p. The capillary venous 
plexus, ramifying upon the 
uriniferous tube. This plexus 
receives its blood from tho 
efferent veins, 2, 2, and trans- 
mits it to the branch of the 
renal vein, v. 



410 OF THE ABDOMEN. 

and their use is not known. Thej are iisnally classed witli 
tlie thymus and thyroid bodies, and are supposed to perform 
some function connected with foetal life. In the foetus they 
are nearly as large as the kidneys. They are well supplied 
with bloodvessels. 

The abdominal viscera having been removed and examined, 
the student may now proceed to dissect the vena cava and 
the aorta, with such of their branches as have not already 
been noticed. The thoracic duct, the sympathetic cord, the 
branches of the lumbar plexus of nerves, and some of the 
deep muscles will also be included in this dissection. 

The AoETA, Fig. 177 (7), will be seen entering the cavity 
of the abdomen between the crura of the diaphragm, where it 
rests on the bodies of the last two dorsal vertebrae. It ex- 
tends down to the fourth lumbar vertebra, where it divides into 
the common iliacs. It is placed somewhat on the left side of 
the bodies of the vertebra over which it passes. The parts 
placed in front of it have been, for the most part, removed, 
or have already been examined. They are, the liver, the 
stomach, the pancreas, the solar plexus, the vena portae, the 
lower portion of the duodenum, the transverse colon, the 
transverse mesocolon, the small intestines, the mesentery, the 
aortic plexus, and the left renal vein. The vena cava ascen- 
dens, the thoracic duct, the vena azygos, and the right semi- 
lunar ganglion lie on its right side. On its left side are the 
left semilunar ganglion, the left supra-renal capsule, and the 
peritoneum, which covers the lower part of it, both in front 
and on the left side. The left lumbar veins pass hehind it. 

The Phrenic Arteries, Fig. 177, and Fig. 159 (1), arise 
from the aorta separately or in common, near the cceliac. 
The left one passes upwards and outwards behind the oesopha- 
gus, to ramify on the under surface of tKe left portion of the 
diaphragm. The right one passes behind the vena cava, and 
is distributed to the under surface of the right portion of the 
diaphragm. They anastomose with each other, and with 
branches of the internal mammary and intercostal arteries. 
They do not always, or both of them at least, arise from the 
aorta. 

The lumlar arteries^ Fig. 159(8), and Fig. 177, consist of four 
or five pairs. They correspond to the intercostal arteries. 
They arise from the posterior aspect of the aorta, and pass 



DISSECTION OF THE DEEP VESSELS AND NERVES. 411 

outwards on tlie bodies of tlie vertebra3. The upper two on 
each side go behind the cms of the diaphragm and the lower 
two or three behind the psoas magnns. Each divides into an 
abdominal and a dorsal branch. The latter, after sending a 
branch through the intervertebral foramen to the spinal canal, 
goes to the muscles and integument of the back. The former 
pass behind the quadratus lumborum, and supply brancbes 
to the posterior abdominal parietes. They anastomose with 
the intercostal, the internal circumflex ilii, and the ilio-lumbar 
arteries. These arteries maybe dissected on one side, leaving 
the psoas magnus and the nerves to be examined on the 
other ; or they may all be dissected at the same time. 

The middle sacral artery, Fig. 159 (12), arises from the 
posterior part of the aorta, just above its bifurcation. It is 



Fig. 177. 




A View of thr Urinary Organs in Situ. — 1, 1. The kulnoys. 2. 2. Tho oap- 
sulfc renalos. 3,3. Tho ureters in their eouvso to tho bhiddor. and their rohitions to 
tho bk-)odvcssels, 4. Bhidder distended ^vith urine. 5. The rectum. I), (5. The 
einulgent arteries. 7. The abdominal aorta. 8. Its division into tho iliacs. 9, 9. 
Tho primitivo iliaca at tho points where tho ureters cross them. 



412 OF THE ABDOMEN. 

directed downwards on the sacrum into the pelvis. It may 
be traced a short distance in this stage of the dissection, but 
it cannot be followed out in its distribution until the pelvis 
is dissected. 

The Common Iliac Arteeies, Fig. 177 (s), arise from the 
bifurcation of the aorta, and are directed downwards and out- 
wards to the sacro-iliac symphyses. Each is from an inch and 
a half to two inches in length. The peritoneum and fila- 
ments of the sympathetic nerve, and sometimes the ureter, lie 
in front of it. The right one is usually somewhat longer 
than the left, on account of the aorta being placed to the left 
side. They diverge more in the female than in the male. 
Opposite to the sacro-iliac symphysis each divides into the 
external and internal iliac. 

The External Iliac Artery, Fig. 177, on each side is 
directed downwards and outwards along the brim of the pelvis 
to Poupart's ligament. It is covered by peritoneum through 
its whole extent. The ureter generally crosses it near its 
origin, and just above Poupart's ligament the vas deferens 
passes over it from without inwards. The psoas magnus lies 
at first on the outside of it, and then behind it. The exter- 
nal iliac vein is placed on the inner side of it, except on the 
right side where it passes under the artery near its origin. 
Just before it passes beneath Poupart's ligament it gives off 
the epigastric and the internal circumflex ilii arteries, which 
have been described with the abdominal parietes. The obtu- 
rator artery sometimes has its origin from the external iliac. 

The dissection of the internal iliac artery must be post- 
poned for the present. 

The Yena Cava Ascendens commences below, oppo- 
site the last lumbar vertebra. It is formed by the union 
of the common iliac veins. It ascends, on the right side 
of the aorta, to the cordiform tendon of the diaphragm, 
which it perforates, to join the right auricle of the heart. 
In its course it receives the lumbar, the right spermatic 
or ovarian, the renal, the supra-renal, the phrenic, and the 
hepatic veins. The lumbar and the phrenic veins accom- 
pany their corresponding arteries, and require no particular 
description. The other veins have been noticed. The vena 
cava has no valves. The external iliac veins were observed 
in the dissection of their corresponding arteries. 



DISSECTION OF THE DEEP VESSELS AND NERVES. 413 

The Common Iliac Yeins correspond to the common iliac 
arteries. The left one is longer and more obliqne than the 
right It lies at first on the inner side of the left common 
iliac artery, and then passes under the right common iliac, to 
join the right common iliac vein, which is placed on the 
outer side of its accompanying artery. The middle sacral 
vein opens into the left common iliac. The common iliac veins 
are formed by the junction of the external and internal iliacs. 

The Cord and the Lumbar Canglia of the sympathetic 
nerve, Fig. 142 (i 7), are situated on the bodies of the lumbar 
vertebrse. There are usually three or four ganglia on each 
side. The cord enters the abdomen on each side beneath 
the inner arch of the diaphragm, or the true ligamentum 
arcuatum, continues down along the internal border of the 
psoas magnus muscle, and descends into the pelvis beneath 
the common iliac artery. From the ganglia external and 
internal branches are given off. The external branches pass 
beneath the psoas muscle, and join the lumbar nerves. The 
internal are directed inwards, and form, with filaments from 
the solar plexus, the aortic plexus. Other branches go to 
join the plexu.ses which supply the viscera. 

The aortic plexus terminates in filaments which accompany 
the iliac arteries, and in others which join the hypogastric 
plexus in front of the sacrum. 

The hypogastric plexus is formed by filaments from the 
aortic plexus, and from the lumbar and sacral ganglia. Those 
from the lumbar ganglia reach it by passing over the com- 
mon iliac arteries. It divides into other plexuses which 
accompany the arteries that go to the pelvic viscera. 

The Lumbar Nerves, Fig. 178, consist of five pairs. 
They divide, after leaving the intervertebral foramina, into 
anterior and posterior branches. The latter are distributed 
to the muscles and the integument of the back. The anterior 
branches are much the largest. They enter tlie psoas muscle, 
where they divide and unite again with each other, so as to 
form the lumbar plexus. The first one is connected to the 
last dorsal, and the last two to the sacral nerves. 

The Lumbar Plexus, Fig. 178 (i), is larger below than 
above. It is placed at the sides of the lumbar vertebra?, and 
in the posterior part of the psoas muscle. It gives oil' the 

35^ 



414 



OF THE ABDOMEN. 



following nerves: The superior muscnlo-cutaneous or ilio- 
scrotal, tlie middle musculo-cutaneons, the inferior mnsculo- 
cutaneous or external cutaneous, the genito-crural, the anterior 
crural, and the obturator. The superior and middle musculo- 
cutaneous have been described with the abdominal parietes. 

The Infekior MuscuLo-CuTAisrEous, or External Cuta- 
neous Branch, Fig. 178 (4), usually arises from the second 
lumbar nerve, leaves the psoas muscle, and passes over the 
iliacus internus to Poupart's ligament, near the anterior supe- 
rior spinous process of the ilium. It goes under the ligament 
and supplies the integument on the outer part of the thigh. 
It is bound down by fascia in the iliac fossa. 

The Genito-Crural Nerve, Fig. 178 (9), arises from the 

Fig. 178. 




a View of the Lumbar and Sacral Plexuses and the Branches of the 
Former. — 1. The lumbar plexus. 2. The sacral plexus. 3,3, Superior and middle 
musculo-cutaneous nerves. 4. Inferior musculo-cutaneous nerve. 5,6,7. Cutane- 
ous branches from 8. The anterior crural nerve. 9. The genito-crural nerve. 10, 
10. The lower termination of the great sympathetic. 11. The iliacus internus 
muscle. 12. The three broad muscles of the abdomen. 13. The psoas magnus 
muscle. 14. The bodies of the lumbar vertebra. 15. The quadratus lumborum 
muscle. 16. Tho diaphragm. 17. The sartorius. 



DISSECTION OF THE KECEPTACULUM CHYLI. 415 

second and third lumbar, pierces tlie psoas mnscle, and des- 
cends on its anterior surface, to divide into its genital and 
crural branclies. The division may take place in the muscle. 
The genital branch enters the inguinal canal, and joins the 
spermatic cord, but does not form a part of it. It is dis- 
tributed to the scrotum, in the male, or the external labia 
in the female. The crural hrancJi passes through the crural 
ring, and is lost on the anterior part of the thigh. 

The Anteeior Crural Kerve, Fig. 178 (s), arises prin- 
cipally from the third and fourth lumbar. It pierces the 
psoas muscle, and gets in the groove between it and the 
iliacus internus. It passes beneath Poupart's ligament, about 
half an inch to the outer side of the femoral artery. It sends 
small branches to the psoas and iliacus internus muscles. 

The Obturator Nerve arises from the third and fourth 
lumbar, and passes downwards on the inner side of the 
psoas muscle, and behind the external iliac vessels to the 
opening in the upper part of the obturator ligament. It 
is distributed to the muscles and integument on the inner 
part of the thigh. It also sends filaments to the hip -joint. 
Sometimes there is an accessory obturator nerve which arises 
from the third and fourth lumbar, and descends on the inner 
side of the psoas to the pubic bone, over which it passes to 
the thigh. It sends filaments to the pectineus and adductor 
brevis, to the hip -joint, and others to unite with the obturator 
nerve. 

A fasciculus from the fourth and the whole of the fifth 
lumbar nerve descends into the pelvis to join the sacral 
plexus and to form the superior gluteal nerve. It is named 
the lumbosacral nerve. 

The Eeceptaculum Chyli, Fig. Ill (12), or the com- 
mencement of the thoracic duct, should be sought by the 
student. It is placed in front of the second lumbar vertebra, 
and between the right crus of the diaphragm and the aorta. 
The vena az^^gos is situated on the right side of it. It re- 
quires a little care to distinguish it from the areolar tissue 
around it. It is formed by the union of three or four lym- 
phatic trunks. 

The Iliac Fascia should be examined before the iliacus 
and psoas muscles arc dissected. It is attached to the outer 



416 OF THE ABDOMEN. 

twO'tliirds of Poupart's ligament, where it is continuous 
witli tlie fascia transversalis, to tlie whole of tlie inner border 
of the crest of the ilium, to the ligamentum arcuatum ex- 
ternum, to the bodies of the lumbar vertebra, and to the brim 
of the pelvis. The lower part is thicker and more aponeuro- 
tic than the upper and inner part. It covers the psoas and 
iliacus internus muscles. The external iliac artery and vein 
lie in front of it. Where these vessels pass beneath Pou- 
part's ligament, a process of the iliac fascia is prolonged down 
behind them, which, joined to a similar prolongation of the 
fascia transversalis in front of the vessels, forms a funnel- 
sliaiped sheath around them. This will be noticed more par- 
ticularly in the dissection of the parts concerned in femoral 
hernia. 

It will be observed, from the attachment of the iliac fascia, 
that when pus collects beneath it, it will have a tendency to 
follow the psoas and iliacus muscles to the upper and anterior 
part of the thigh. 

The Psoas Magnus, Pig. 178 (13), arises from the margins 
of the bodies of the lower two dorsal and the upper four lum- 
bar vertebrae, from the intervertebral substance, from the 
ligamentous bands which arch over the grooves on the sides 
of the bodies of the vertebra, and from the bases of the trans- 
verse processes. The fibres proceed downwards and some- 
what outwards along the brim of the pelvis, beneath Pou- 
part's ligament, and end in a tendon which passes backwards 
and inwards over the capsular ligament of the hip-joint, and 
is inserted into the posterior part of the small trochanter. A 
bursa is placed between its tendon and the pubic bone and the 
capsular ligament. There is also a sr)iall bursa between it 
and the trochanter. The lumbar arteries and the nerves of 
communication betvfeen the lumbar and the sympathetic pass 
in the grooves on the bodies of the vertebrae, beneath the 
tendinous arches from which this miiscle in part arises. The 
action of the psoas is to flex the thigh on the pelvis, or the 
body on the thigh. Prom the position of the trochanter 
minor this mu.scle rotates the thigh outwards before flexing 
it bn the body. 

The Psoas Paevus is frequently wanting. When present, 
it is situated mainly in front of the psoas magnus. It arises 
from the bodies of the last dorsal and the first lumbar ver- 



DISSECTION OF THE DIAPHRAGM. 417 

tebrse, and from the intervertebral substance between them. 
The fibres pass downwards, and terminate in a thin fiat ten- 
don, which is inserted into the brim of the pelvis and into 
the iliac fascia. As it descends it crosses the psoas magnus 
from without inwards. Its action is to render the iliac fascia 
tense, and, through it, Poupart's ligament. It may also assist 
in flexing the pelvis on the spine. 

The Iliacus Internus, Fig. 178 (i i), arises from the whole 
of the iliac fossa, from the ilio-lumbar ligament, from the an- 
terior spinous processes of the ilium and the notch between 
them, and from the capsular ligament of the hip-joint. The 
fibres converge and pass downwards and inwards to end in 
the tendon of the psoas magnus with which it is inserted into 
the trochanter minor. A portion of its fibres are inserted 
directly into the shaft of the femur just below the trochanter. 
Its action is similar to that of the psoas magnus. These mus- 
cles are concerned in walking; as, in raising and moving the 
lower extremity forwards. When they act on both sides and 
the thighs are fixed, they bend the body forwards. 

The DiAPHRAGl^i, Fig. 179, forms a muscular septu.m be- 
tween the thoracic and abdominal cavities. Its upper sur- 
face is covered by the pleurae and the pericardium, and is 
in relation with the thoracic viscera; its lower surface is 
principally covered by the peritoneum, and is in relation with 
the viscera of the abdomen. The peritoneum is easily re- 
moved by dissecting and peeling it off before the cavity of 
the thorax is opened, as the muscle is then tense. It is usu- 
ally described as consisting of a greater and a lesser muscle, 
which are connected by a central tendon. 

The greater muscle, Fig. 179 (i, 2, s), forms the anterior 
and lateral portions ; the lesser 7mcscle, Fig. 179 (s, 10), forms 
the posterior part. The first ames from the ensiform carti- 
lage, the last true and all the false ribs, and from the liga- 
menta arcuata, externum and internum. Its origin from the 
ensiform cartilage consists of one or two fasciculi, with a 
small triangular space on each side, in which the anterior 
mediastinal space is separated from the abdomen only by 
peritoneum. Viscera of the abdomen may be forced through 
these spaces into the thorax, producing d)'aj-)hra(j))}atic hernia ; 
or pus may escape from the mediastinum through them into 



418 



OF THE ABDOMEN. 



the abdomen. Its costal attacliments form indigitations with, 
the transversalis muscles. 

Fig. 179. 




The Under or Abdominal Side of the Diaphragm. — 1, 2, 3. The greater 
muscle; the figure 1 rests upon the central leaflet of the tendinous centre; the 
number 2 on the left or smallest leaflet ; and number 3 on the right leaflet. 4. 
The thin fasciculus which arises from the ensiform cartilage ; a small triangular 
space is left on either side of this fasciculus, which is closed only by the serous 
membranes of the abdomen and chest. 5. The ligamentum arcuatum externum of 
the left side. 6. The ligamentum arcuatum internum. 7. A small arched opening 
occasionally found, through which the lesser splanchnic nerve passes. 8. The right 
or larger tendon of the lesser muscle; a muscular fasciculus from this tendon curves 
to the left side of the greater muscle between the oesophageal and aortic openings. 
9. The fourth lumbar vertebra. 10. The left or shorter tendon of the lesser mus- 
cle. 11. The aortic opening occupied by the aorta, which is cut short ofi". 12. 
A portion of the oesophagus issuing through the oesophageal opening. 13. The 
opening for the inferior vena cava, in the tendinous centre of the diaphragm. 14. 
The psoas magnus muscle passing beneath the ligamentum arcuatum internum; 
it has been removed on the opposite side to show the arch more distinctly. 15. 
The quadratus lumborum passing beneath the ligamentum arcuatum externum; 
this muscle has also been removed on the left side. 

The fibres converge from this extended origin, and are in- 
serted into the anterior and lateral borders of the central 
tendon. 

The lesser muscle arises^ tendinous, on the right side from the 
bodies of the upper three or four lumbar vertebrae, and from 
their intervertebral substance ; and on the left side from the 



DISSECTION OF THE DIAPHRAGM. 419 

iirst two or three vertebrse. These portions are named the 
criira^ or pillars of the diaphragm. They pass upwards and 
forwards, and at a short distance in front of the last dorsal 
vertebra are united by a fibrous band, which forms an arch 
over the aortic opening. Above this point they become 
muscular, and by a decussation of their inner fasciculi, 
partly form the oesophageal opening, and separate it from 
the aortic. They spread out, and finally end in the posterior 
part of the central tendon. 

The central or cordiform tendon is composed of three parts, 
called leaflets^ or a?oe, Fig. 179 (i, 2, 3). The middle and an- 
terior one is usually the largest. It corresponds to the peri- 
cardium. The left one is the smallest, and is below the left 
lung. The fibres of this tendon interlace with each other, 
and are also crossed in different directions by accessory 
fibres. 

There are three principal /oramma in the diaphragm. 

The hiatus aorticus^ Fig. 179 (1 1), is situated in front of the 
body of the last dorsal vertebra, and between the crura. 
It transmits the aorta, and sometimes one of the great 
splanchnic nerves. 

The oesophageal opening^ Fig. 179 (12), is placed directly 
behind the cordiform tendon, which sometimes forms a part 
of its anterior boundary. It is to the left, and in front of 
the aortic opening. The decussating fasciculi of the crura 
form its posterior and lateral boundaries. It has been sup- 
posed that these fascicu.li might act as a sort of sphincter 
muscle to the oesophagus, as it passes through this opening. 
The oesophagus and the pneumogastric nerves pass through 
it. The aortic and oesophageal foramina lead from the cavity 
of the abdomen into the posterior mediastinum. 

The foramen quadrattim^ Fig. 179 (13), is situated to the 
right side of the median line, and considcrabl}^ anterior to 
either of tbe others. It is placed in the posterior part of 
the right leaflet, and is wholly surrounded by tendinous 
fibres ; thus the vena cava is not liable to be compressed by 
the action of the diaphragm. It transmits the ascending 
cava and a few filaments of the phrenic nerve. 

The sympathetic, and the greater and lesser splanchnic 
nerves, and also the left azygos vein, pass through small 
foramina in the diaphragm. 

The diaphragm is a muscle of inspiration. When it acts, 



420 OF THE PELVIS. 

the lateral mnscular portions descend, and tlie fibres assume 
nearly a horizontal direction. It also assists tlie mnscles of 
the abdomen in compressing the abdominal viscera, &c. The 
cordiform tendon is subject to but very little movement. 

The LiGAMENTUM ArCUATUM EXTERNUM, Tig. 179 (s), 

extends from the transverse process of the first lumbar ver- 
tebra to the last rib. It forms a fibrous arch over the 
quadratus lumborum muscle. It is the upper border of the 
anterior lamina of the fascia lumborum. 

The LiGAMENTUM ArCUATUM INTERNUM, Kg. 179 (e), 

passes from the body of the second lumbar vertebra to the 
transverse process of the first. It forms a fibrous arch over 
the psoas magnus and the sympathetic nerve. 



Sect. III. — Dissection of the Pelvic Yiscera. 
The Eectum. 

The Eectum, Fig. 167 (s), is the last portion of the ali- 
mentary canal. It occupies the posterior part of the pelvic 
cavity, and extends from the sigmoid flexure of the colon to 
the anus. In an antero-posterior direction it presents only 
a single curvature, which corresponds to that formed by the 
sacrum and os coccygis, until it reaches the lower part of the 
coccyx, where it is inclined a little backwards. The upper 
part of it is directed, laterally, from a point opposite the left 
sacro-iliac junction to the median line in the lovfer part of 
the hollow of the sacrum. 

It is from six to eight inches in length. It is cylindrical, 
but not sacculated, like the colon. The upper part of it is 
somewhat constricted, but the lower part, to within a short 
distance of the anus, is expanded into a pouch-like dilatation, 
below which it is again contracted. 

The rectum has the same number of layers in its walls as 
the other divisions of the intestinal canal, except the lower 
third, which has no serous covering. The muscular coat is 
much thicker than that of the colon or small intestine, re- 
sembling in this respect the oesophagus. 

The longitudinal fibres are not arranged in bands as they 
are in the colon, but are distributed equally on all sides, as 



DISSECTION OF THE BLADDER. 421 

in the small intestine. Some of them terminate in the ex- 
ternal sphincter of the anus ; others are reflected inwards 
and upwards around the internal sphincter, and are lost in 
the submucous areolar tissue from half an inch to an inch 
above the anus. 

The circular fibres are collected into quite a large fasci- 
culus at the lower end of the rectum, forming what is called 
the internal sphincter of the anus. 

The mucous membrane of the rectum presents a number of 
large irregular folds, which are not wholly obliterated when 
the bowel is distended. At the lower end of the bowel there 
are several small longitudinal folds, between which depres- 
sions exist, and in which foreign substances are sometimes 
lodged. The mucous membrane in the lower part of the 
rectum is very loosely connected to the muscular layer. 
Hence prolapsus of it sometimes occurs. 

The arteries of the rectum are the superior, the middle, 
and the inferior Jiemorrlioidal. The superior are branches of 
the inferior mesenteric; the middle^ of the internal iliac; and 
the inferior^ of the internal pudic. The rectum is more vas- 
cular than any other portion of the large intestine. 

The veins are named the superior, middle, and inferior 
hemorrhoidal. A plexus of veins is found beneath the mu- 
cous membrane in the lower part of the rectum, which, by 
becoming varicose, forms hemorrhoids. This plexus com- 
municates with the vesical plexus. The hemorrhoidal veins 
empty partly into the inferior mesenteric, and partly into the 
internal iliac. 

The nerves of the rectu.m are derived from the sympathetic 
system, and from the sacral plexus. 



Dissection of the Bladder. 

The Bladder should be examined in sitd^ when distended 
as well as when empty, in order to understand its relations 
to the surrounding parts in both of these conditions. To 
study its structure, it should be removed from the pelvis 
together with the prostate gland and the penis. It varies 
greatly in size in difterent individuals, and under diftcrent 
circumstances. It is said to be larger and more globular in 
the female than in the male. 
36 



422 OF THE PELVIS. 

Its parietes are composed of a serous, a muscular, a cellu- 
lar, and a mucous layer. 

The Seeous Later is found only on the upper, posterior, 
and lateral portions. The anterior surface has no serous in-' 
vestment, nor have the sides anteriorly ; and the same is true 
of the lower part posteriorly, especially when the bladder is 
distended. The serous layer is loosely connected to the one 
beneath it by areolar tissue. 

The Muscular Later, Fig. 186, consists of three sets 
of fibres or fasciculi, a longitudinal, a circular, and a reticu- 
lar. To examine the muscular structure of the bladder, it 
should be distended with air or some suitable material, as 
hair or tow. 

The longitudinal fibres are placed on the outside. They 
are spread out over the entire organ, and terminate below 
at the neck of the bladder; some of them are inserted 
into the cervix, others enter the substance of the prostate 
gland, and a few are attached to the anterior ligament of the 
bladder and through it to the pubic bone. 

The circular fibres are thinly scattered over the body of 
the bladder, but increase in number towards the cervix, where 
they form what has been regarded by some as the sphincter 
vesicce. 

The reticu lar fibres are very irregular in their distribution. 
They cross each other in different directions, and give to the 
interior of the bladder a reticulated appearance. Sometimes 
these fasciculi become so large that quite deep crevices are 
found between them, into which the mucous membrane is 
reflected, forming pouches in which calculi are sometimes 
lodged. When these pouches exist, the bladder is said to be 
sacculated. 

The Cellular Later is placed between the muscular and 
mucous, and requires no particular description. 

To examine the Mucous Later, Fig. 180, and the in- 
ternal appearance of the bladder, it should be laid open along 
the median line in front. The mucous membrane is thin, 
soft, and of a pale color, and presents numerous folds, most 
of which are transverse. These rugae, however, disappear 
when the bladder is filled. Mucous follicles may be seen, 
especially in the neighborhood of the cervix. The orifices 
of the ureters and of the urethra, with the triangular space 



DISSECTION OF THE BLADDEE. 



423 



Fig. 180. 



called tlie trigone, will be observed in tlie lower and posterior 
part of the bladder. 

The trigone^ or vesical triangle. 
Fig. 180 (7), is the small space 
between the three orifices of the 
bladder. The rugae, which are 
seen in other parts of the blad- 
der, are here absent, the surface 
being smooth, with the excep- 
tion of some fine strise, which 
are directed towards the orifice 
of the urethra. 

The orifices of the ureters, Fig. 
180 (3, 3), which appear like 
small slits in the mucous mem- 
brane, are situated at the pos- 
terior angles of the trigone. The 
distance between them varies ac- 
cording as the bladder has been 
contracted or distended. A probe 
should be passed through the 
orifice of one of the ureters, to 
show the oblique manner in 
which it perforates the coats of 
the bladder. It will be found to 
traverse three-fourths of an inch 
or more of the cellular layer after 
perforating the muscular coat. 
This arrangement prevents the 
contents of the bladder, even 
when it is filled with air, from 
passing into the ureters. 




20 21^ 



The Bladder and Urethra op a Man laid open in its whole Length. — 1, 1. 
The bladder cut open by a crucial incision, and the four Haps separated. 2, 2. The 
ureters. 3, 3. Their vesical orifices. 4. Uvula vosicto. The triangle formed by the 
points at 3, 3, 4, is the vesical triangle. 5. Superior fundus of the bladder. 0. l>as 
fond of the bladder. 7. The smooth centre of the vesical triangle. 8, Verumon- 
tanum, or caput gallinaginis. 9. Orifice of the ductus cjaculatorius. 10. Depression 
near the verumontanum. 11. Ducts from the prostate gland. 12,13. Lateral lobes 
of the prostate gland. 14. Prostatic portion of tho urethra : just above is the nock 
of tho bladder. 15. Membranous portion of tho urethra. 16. One of Cowpor's 
glands. 17. The orifices of their excretory ducts, 18, 18. Section of the bulb of 
tho urethra with its erectile tissue. 19, 19. Cut edges of the corpora cavernosa. 
20. Cut edges of the glans penis. 21. Prepuce dissected oft'. 22. Internal surface 
of tho urethra laid open. 23, 23. Outer surfaces of corpora cavernosa. 24, 25. Ac- 
celerator urina) muscles. 26, 27. Erector penis muscles. 28, 29. Vasa defereutia. 



424 OF THE PELVIS. 

The uvvM vesicae^ Fig. 180 (4), is a slight elevation seen at 
the apex of the trigone, and near the orifice of the urethra. 
It is formed by a thickening of the submncons areolar tissne, 
and corresponds to the third lobe of the prostate gland. 

If the mucous membrane of the trigone be dissected off, a 
strong fasciculus of muscular fibres will be found situated 
at its base, extending between the orifices of the ureters ; 
and also a fasciculus going from the orifice of each of the 
ureters to the uvula. The last have been called the muscles of 
the ureters^ or the muscles of Bell^ as they were described by 
him. A layer of dense, white fibrous tissue is found imme- 
diately beneath the mucous membrane in the trigone. It is 
on account of this structure, to which the mucous membrane 
is closely adherent, that no rugae or folds are found in this 
part of the bladder. 

The Nech of the bladder, although its limits are not de- 
fined by any natural lines of demarcation, may be considered 
as that part which is applied to the base of the prostate gland. 
It is surrounded above and laterally, on the outside of the 
mucous membrane, by a fibro-muscular tissue, which is sup- 
posed to act as a sphincter muscle. Many of the longitudinal 
fibres of the bladder are inserted into this structure. 



DlSSECTIOX OF THE PeOSTATE GlAXD, 

The Peostate Glaxd, Pig. 181 (7), surrounds the neck of 
the bladder and the upper portion of the urethra. It is of a 
conical shape, with its base applied to the bladder. Its trans- 
verse diameter is about an inch and a half, its antero- 
posterior an inch and a quarter, and its vertical from three- 
fourths of an inch to an inch. The antero-posterior diameter 
is in the direction of the urethra. Its relations to the sur- 
rounding parts are described with the pelvic viscera in situ. 
The urethra passes through the upper part of it, having only 
about one-third of the gland above it ; it varies, however, a 
great deal in this respect. It consists of three lohes. two 
lateral and a middle. The latter is quite small ; it is placed 
behind and between the other two, and is partly separated 
from them by a notch which is occupied by the common 
ejaculatory ducts. The uvula vesicae is situated directly 
above it. 

The prostate is composed of numerous granules^ which are 



DISSECTION OF THE UEETHKA. 425 

arranged so as to form lobules. These are compressed closely 
together, so that the gland has quite a dense, solid feel. It 
is traversed by muscular fibres, which come from the bladder. 
Its ducts, varying from ten to fifteen in nuniber, open into 
the urethra on each side of the caput gallinaginis. Small 
calculi sometimes lodge in the mouths of these ducts. 



The Ueethka. 

The Ueethea is from seven to nine or ten inches in length, 
extending from the bladder to the end of the penis. It is 
composed of a mucous membrane, supported by a layer of 
areolar tissue, in which is observed longitudinal bands, sup- 
posed by some to be muscular, and by others fibrous. It is 
divided into three parts, each of which requires special 
notice, not only on account of its peculiar appearance, but on 
account of its relations to contiguous parts. The three divi- 
sions are named the prostatic, the membranous, and the spongy. 
In specifying the relative length of these divisions, the ure- 
thra will be supposed to be nine inches long. 

The Peostatic Poetion, Fig. 180 (14), is an inch and a 
quarter in length. It is shaped like a wine-cask, being larger 
in the middle than at the extremities. At the bottom of it 
in the median line is a prominence named the caput gallina- 
ginis^ or verumontanum^ Fig. 180 (s). On the summit of this 
and near the middle, is the sinus pocularis^ or utricle^ which 
extends a short distance downwards and backwards in the 
direction of the common ejaculatory ducts which not unfre- 
quently open into it. On each side of the verumontanum is 
a depression, named the prostatic sinus, Fig. 180 (11). Tlie 
ducts of the prostate gland open into these sinuses, except 
those of the middle lobe, which open just behind and above 
the verumontanum. This portion of the urethra is sur- 
rounded by tlio prostate gland, and by the muscular coat of 
the bladder, which is prolonged downwards immediately 
around the urethra as well as into the substance of the gland. 

The Membeanous Poetion, Fig. 180 ( 1 5), and Fig. 181 ( 1 ), 
is about tliree-fourths of an inch in length. It extends from 
the prostatic to the spongy portion. It passes through the tri- 
angular ligament, which fixes it firmly in its position. It is 

30^^ 



426 



OF THE PELVIS. 



covered bj an erectile elastic tissue, by the muscles of Wil- 
son and Gutlirie, and bj a layer of the deep perineal fascia. 
The caliber of its anterior extremity is smaller than that 
of any other part of the urethra, except the external orifice. 

Fig. 181. 




A LoxGiTrDiNAL Section of the Bladder, Prostate Glaxd, axd Pems, show- 
ing the Urethra. — 1. The urachus. 2. The recto-vesical fold of peritoneum. 3. 
The opening of the right ureter. 4. A slight ridge, formed by the muscle of the 
ureter. 5. The commencement of the urethra : the elevation of mucous membrane 
immediately below the number is the uvula vesicas. 6. The prostatic portion of the 
urethra. 7. The prostate gland. 8. The isthmus, or third lobe of the prostate ; 
immediately beneath -which the ejaculatory duct is seen passing. 9. The right 
vesicula seminalis. 10. The membranous portion of the urethra. 11. Cowper's 
gland of the right side, with its duct. 12. The bulbous portion of the urethra. 13. 
The fossa navicularis. 14, The corpus cavernosum. 15, The right crus penis. 
16. Near the upper part of the corpus cavernosum, the section has fallen a little to 
the left of the middle line; a portion of the septum pectiniforme is consequently 
seen. 17. The glans penis. 18. The lower segment of the glans. 19. The meatus 
urinarius. 20. The corpus spongiosum, 21. The bulb of the corpus spongiosum. 

The Spongy Portion is about seven inches in length, Fig. 
181. It presents two enlargements: the hulhous, and the 
fossa navicularis. The former. Fig. 181 (12), is situated in 
the lower part and near its commencement, and the latter, 
Fig. 181 (13), which is a lateral dilatation, near the meatus. 
Just in front of the bulbous portion are seen, on the lower 
surface, the orifices of the ducts of Cow])er''s glands^ Fig. 
181 (11). Crypts^ or lacimce, are found distributed over the 
whole surface. Some of these are the external orifices of 
canals which run backwards from half an inch to an 
inch beneath the mucous membrane. A very large one is 
sometimes met with on the upper surface, and about three- 



DISSECTION OF THE PENIS. 



427 



quarters of an inch from the meatus ; it is named the lacuna 
magna. A small, pointed catheter, or bougie, may enter 
one of these lacunae, especially if it should happen to be 
unusually large. The meatus urinarius^ Fig. 181 (i 9), is the 
external orifice of the urethra. It is a vertical slit in the 
lower and anterior part of the gJans. The spongy portion 
of the urethra is surrounded by the corpus spongiosum, and 
the upper part of it also by the acceleratores muscles. 

The CoKPUS Spongiosum, Fig. 181 (20), consists of a de- 
licate erectile tissue, which surrounds the spongy portion of 
the urethra. It is expanded posteriorly to form the bulb, 
and anteriorly, to form the glans penis. It is thicker below, 
and on the sides of the urethra, than above it. It is covered 
by a thin fibrous lamina, from the inner surface of which 
numerous processes or trabeculge project into its substance, 
and form there a fine network. The hulh is quite promi- 
nent, and projects backwards to the extent of three or four 
lines beneath the membranous part of the urethra. It is 
covered by a fibrous lamina reflected from the triangular 
ligament or deep perineal fascia. 

The Glans Penis, Fig. 182, forms the head of that organ. 
It is of a somewhat conical shape. Its structure is the same 
as that of the corpus spongiosum. Its 
base is oblique from above downwards and 
forwards, and is excavated behind for the 
reception of the anterior extremities of the 
corpora cavernosa, over which the margin 
of its base projects and forms the corona 
glandis. It is much longer above than be- 
low, where there is a slight groove for the 
attachment of the frmnum proiputii. 

The Corpora Cavernosa, Fig. 181 
(14), form the body of the penis. They 
consist of a spongy erectile tissue, in- 
closed in a dense white fibrous membrane. 
They are firmly attached, posteriorly, to 
the rami of the ischia, and the descend- 
ing rami of the pubcs. From these 
points of attachment they are directed 
upwards and forwards, increasing in size, 
to a point opposite the symphysis pubis, 
where they are joined to each other; 



Fig. 182. 




A View op the Glans 
Penis in.iectep. — 1. 
Portions of tho corpora 
cavernosa. 2. Tho pre- 
puce turned back. 3. 
Its tVaMiuui, 4, 4. Glan- 
dular odorifora> Tysoni. 
f). Point of the glans pe- 
nis. 0. Prominences of 
the glans on each side of 
the fraMunn. 7. The fur- 
row which separates tho 
sides of tho glans. S. 
Corona glandis. 



428 



OF THE PELVIS. 




A Section of the Corpoea 
Cavernosa Penis 1, 1, and Cor- 
pus Spongiosum Urethrje 4. — 
2, 2. Erectile tissue of the corpora 
cavernosa. 3. Septum pectini- 
forme. 5. Canal of the urethra. 
6. Internal filaments of the cor- 
pora cavernosa which pass from 
the median septum to the external 
fibrous membrane. 



these portions of them are named 
the crura, Fig. 181 (is). They 
terminate anteriorly in a rounded 
extremity, without any line -of se- 
paration between them. They 
present a groove on the under sur- 
face in the median line for the 
lodgment of the urethra, and one 
above, which is occupied by the 
dorsal vessels and nerves of the 
penis. Internally they are sepa- 
rated by the septum pectiniforme, 
Fig. 183 (3). This is a perfect 
septum posteriorly, but consists, 
anteriorly, of fasciculi, which are 
connected above and below to the 
parietes common to the two bodies, 
resembling, as the name implies, 
the teeth of a comb. These fasci- 
culi are loosely connected together 
anteriorly by areolar tissue. From the incompleteness of this 
septum, and the intimate connection existing between the 
two bodies, they might be regarded as constituting but one. 
From the inner surface of the walls of the corpora cavernosa 
processes are sent internally, which intersect and unite with 
each other so as to form a complete network. Fig. 183 (e). 
The trabecular arrangement is mu.ch coarser in these bodies 
than it is in the corpus spongiosum. The traheculce contain 
more or less of yellow fibrous tissue. There is very little if 
any vascular connection between the corpora cavernosa and 
the glans penis. 

The GrLAN-DS OF CowPEE, Fig. 181 (11), are two small 
bodies located just behind the bulb of the urethra. These 
ducts open into the urethra anterior to the sinus of the bulb ; 
they are about an inch in length. 

The Skin which covers the penis is very thin, extensible, 
and free from hair bulbs. It is connected to the parts be- 
neath it by loose areolar tissue, which allows it to move on 
the parts which it covers with great facility. This areolar 
tissue contains no fat, but is very liable to be distended by 
serous effusions. It contains, on the dorsum, posteriorly, the 



DISSECTION OF THE PENIS. 429 

fibres wliicli descend from tlie linea alba to form the super- 
ficial suspensory ligament of the penis. Some yellow elastic 
fibres are usually found in this ligament. 

The Prepuce, Fig. 182 (2), is formed by a duplicature of 
the skin, wHch projects over and sometimes beyond the 
glans penis. The reflected portion of it assumes the charac- 
ter of a mucous membrane, and is continued from the cervix 
over the glans to the orifice of the urethra, where it be- 
comes continuous with the lining membrane of that canal. 
When the prepuce covers the glans so as to confine it, it 
forms what is called pJiymosis, When it becomes constricted 
behind the corona, it forms parapJiymosis. 

In the cervix, or depression behind the corona, there are 
some sebaceous glands, named the glandulce odoriferce Tysoni, 
Fig. 182 (4, 4). 

The froenum prceputii^ Fig. 182 (3), consists of a triangular 
fold of the mucous membrane, which is attached to the groove 
in the glans just below and behind the meatus urinarius. 

The arteries of the penis are derived principally from 
the internal pudic. The corpus spongiosum is supplied 
by the bulbous branches, which penetrate the bulb. The 
branches which are distributed to the corpora cavernosa 
enter the crura; they are called the arteries of the corpora 
cavernosa. The glans, the prepuce, and the skin, are sup- 
plied by the dorsal branches, which reach the dorsum of the 
penis by passing between the crura and perforating the sus- 
pensory ligament. The arteries which enter the spongy and 
cavernous bodies divide into a great number of branches ; 
some of which are appropriated to the nourishment of the 
tissues, and others terminate by communicating freely with 
the venous plexus in the intertrabecular spaces. 

The veifis of the penis are large ; they arc divided into the 
dorsal or superficial^ and the veins of the corpora cavernosa. 
The dorsal pass backwards beneath the sjaiiphysis pubis, and 
between the crura, to terminate in the prostatic and vesical 
plexuses, while those of the corpora cavernosa end in the 
internal pudic veins. The veins which proceed from the 
spongy structure commence by dilatations, which form plex- 
uses in the intertrabecular spaces. 

The nerves of the penis are derived mainly from the in- 
ternal pudic. 



430 OF THE PELVIS. 



Dissection of the Testicles. 

The genital organs consist of the testicles, which secrete 
the semen, and the apparatus necessary for its transmission 
from the body ; a part of their excretory apparatus, as the 
urethra, is common to both the genital and the urinary organs. 
The urethra, with the penis, has already been examined. 
Before examining the testicles, the coverings which they 
have independently of their proper tunics should be dis- 
sected. Being situated in the abdomen, in the early part 
of foetal life, they obtain these investments in their descent 
into the scrotum. If the student has become familiar with 
the coverings of the bowel in oblique inguinal hernia, he 
will have little or no difficulty in understanding the different 
layers which cover the testicle. They are the following, 
proceeding from withou.t inwards : — 

The integument forms a pouch common to both testicles ; 
it is named the scrotum. It is very thin, of a dark color, 
more or less wrinkled, and covered with hairs. A ridge is 
seen in the median line, called the raphe ; this is continued 
backwards in the perineum, and forwards on the under sur- 
face of the penis. 

The dartos is placed immediately beneath the skin, with 
which it is closely connected. It is continuous with the su- 
perficial fascia of the groin and the perineum. It forms two 
pouches, one for each testicle ; the septum is attached above 
to the under surface of the penis. The dartos is composed 
principally of areolar tissue and non-striated muscular fibres. 
It supports the testicles, and when it contracts, necessarily 
corrugates the skin which is adherent to it. 

The intercolumnar or spermatic fascia is derived from the 
margins of the external abdominal ring. The upper part of 
this contains some fibres prolonged downwards from the in- 
tercolumnar fibres. 

The cremaster muscle consists in the scrotum of loops of 
scattered fasciculi connected together by condensed areolar 
tissue. The term cremasteric fascia has been applied to these 
fasciculi and the connecting areolar tissue. 

The fascia transversalis is prolonged around the spermatic 
cord into the scrotum, and forms one of the coverings to the 
testicle. 



DISSECTION OF THE TESTICLES. 431 

The Tunica Vaginalis, Fig. 184 ( i ), was, before the descent 
of the testicle, a portion of the peritoneum. The testicle, 
while in the abdomen, is covered by the peritoneum in the 
same manner as the spleen or the liver, and when it descends 
into the scrotum carries along with it, not only the portion 
which adheres to its proper tunic, the tunica alhuginea^ but 
also a portion of the peritoneum which is attached to the 
walls of the abdomen. Hence the tunica vaginalis presents 
two portions, one of which is still adherent to the tunica 
albuginea, while the other is reflected over the inner surface 
of the pouch formed by the prolongation of the fascia trans- 
versalis. The latter is denominated the tunica vaginalis re- 
flexa^ and the former, the tunica vagi7ialis testis. They are 
analogous to the parietal and visceral portions of the pleura, 
or of the peritoneum, and, like these membranes, form a 
shut sac. 

In studying the descent of the testicle, the student should 
bear in mind that it was just as much covered by the ^erito- 
neuTUj in the cavity of the abdomen, as it is by the tunica 
vaginalis, in the scrotum, and that the latter is to it in the 
scrotum, what the former was in the abdomen. The tunica 
vaginalis should be studied with reference to the occurrence 
of hydrocele, ko,. 

The testicle is brought into view when the tunica vagi- 
nalis is laid open. It is of an oval form, flattened somewhat 
on the sides. It is about an inch and a half in length, and 
about three-fourths of an inch in thickness, and an inch in 
breadth. Its position in the scrotum is oblique, from above 
downwards, and from before backwards. 

The epididymis is seen attached to its posterior border. 
This presents an upper large extremity, named the globus 
major, and a lower small one called the globus minor; the 
middle portion is named the body. The epididymis is partly 
covered by the tunica vaginalis. Having examined the ex- 
terior of the testicle, the tunica albuginea should be divided, 
and the glandular substance carefully removed, for the pur- 
pose of studying the structure of this tunic. 

The Tunica Albuginea, Fig. 184 (-), is the proper cap- 
sule of the testicle. It is a thick, dense, white fibrous mem- 
brane. It preserves the form of this organ, and protects 
its delicate glandular structure. Behind, it forms a projection 



432 



OF THE PELVIS. 



Fig. 184. 




internally, wliich is named the corpus Ilighmorianiim^ or me- 
diastinum testis^ Fig. 184 (3). From this fibrous bands pass 
off in different directions to be attached 
at various points to the inner surface 
of the tunic. These add yery much 
to the strength of the fibrous structure 
of the testicle, and support the vessels 
as they penetrate the substance of the 
gland. The corpus Highmorianum is 
traversed by the bloodvessels and nerves 
which enter the interior of the testicle, 
and, also, by convoluted seminal tubes. 
It will be observed that from the 
dense and unyielding character of the 
tunica albuginea rapid effusion into the 
interior of the testicle would ^ almost 
necessarily be attended with a great 
deal of pain. 

The Tunica Yasculosa, or PiA 
Mater of the testicle, Fig. 184 (4), 
lines the internal surface of the tunica 
albuginea, and is reflected around the 
fibrous bands attached to its inner sur- 
face. It transmits the vessels to every 
part of the interior of the organ. 

The Glandular Portion of the 
testicle consists of a great number of 
seminal tubes. These may be drawn 
out with the forceps to the extent of a foot or more ; when 
this is done they appear at first like exceedingly fine, deli- 
cate threads, just unravelled from a network. They adhere 
very slightly to each other, and may be easily separated 
when allowed to float in water. They are arranged in lobes 
of a conical shape, and of different sizes ; the bases of which 
look forwards, and the apices backwards. There are from 
three to four hundred of these lobes or bundles of convo- 
luted tubes. Some of them commence by a blind extremity, 
and others are joined together so as to form loops. 

The TuBULi Seminiferi, Fig. 185 (3, 3), unite to form 
about twenty tubes, which are nearly straight ; these enter 



a transverse section 
OF THE Testicle. — 1. The 
cavity of the tunica vagi- 
nalis. 2. The tunica albu- 
ginea. 3. Corpus Highmo- 
rianum or mediastinum 
testis. The cut ends of the 
vessels below the figure be- 
long to the rate testis ; those 
above, to the bloodvessels 
of the testicle. 4. Tunica 
vasculosa of the testis. 5. 
One of the lobules of the 
tubuli seminiferi terminat- 
ing in a vas rectum. 6. A 
section of the epididymis. 



DISSECTION OF THE TESTICLES. 



433 



Fig. 185. 



the corpus Higlimorianiim. Tbey are termed tlie tuhuli rect% 
or vasa recta. These open into the rete testis^ wliicli consists of 
a network of tnbes, in the anterior part of the corpus Highmo- 
rianum. From the rete testis from ten 
to twenty tubes pass through the tunica 
albuginea. They are called the vasa 
efferentia. These are at first straight, 
but become convoluted, and form mass- 
es of a conical shape, which are named 
the coni vasculosi. These cones form the 
globus major or head of the epididymis, 
and by uniting together form a single 
tube, called the canal of the epididymis. 
This tube, after forming the body and 
the globus minor or tail of the epididy- 
mis, terminates in the vas deferens. 

The Yas Deferens, Fig. 185 (lo), 
and Fig. 186 (e, e), commences at the 
lower end of the globus minor, and is 
directed upwards on the inner side of 
the epididymis. It enters the spermatic 
cord at the upper part of the testicle, 
and ascends in the posterior part of it 
to the internal abdominal ring, where 
it leaves the cord, and turning short 
round the epigastric artery, passes down- 
wards and inwards over the external 
iliac vessels, and enters the pelvis. In 
the pelvis it crosses over the ureter, 
gets between the rectum and the blad- 
der, and passes downwards and for- 
wards, on the inner side of the vesicula 
seminalis, to the upper border of the 

prostate gland, where it unites with the ductus vesiculce scmi- 
7ialis, to form the ductus ejaculatorius communis. 

The vas deferens is composed of an inner mucous, and an 
outer fibrous layer. The latter is very thick and firm, so 
that the tube can be distinctly felt in the spermatic cord of 
the living subject. The vas deferens is about two feet in 
Its size does not vary much from its commencement 
37 




A ViETV OF THE MlNUTE 

Structure of*the Testis. 
— 1, 1. Tunica albuginea. 
2,2. Corpus Highmorianum. 
3. 3. Tubuli seminiferi con- 
voluted into lobes, 4, 4. 
Vasa recta. 5. Kete testis. 
6. Vasa efferentia. 7. Coni 
vasculosi constituting the 
globus niojorof the epididy- 
mis. 8. Body of the epidi- 
dymis. 9. Its globus minor. 
10. Vas deferens. 11, Vas 
aberrans, or blind duct. 



length. 



:34 



OF THE PELVIS. 



Fig. 186. 



until it readies tlie bladder, where it enlarges, and becomes 
sacculated. 

The Yas Abeeeans, Fig. 185 (n), is a small tnbe wMcli 
is sometimes found arising from the globus minor, or the 
commencement of the vas deferens, and extending a short 
distance upwards in the spermatic cord. It terminates in a 
blind extremity. Its use is not known. 

The Yesicul^ Seminales, Fig. 186 (7, 7), are two saccu- 
lated bodies, situated on the base 
of the bladder, above the prostate 
gland, and in front of the rectum. 
They are each about two inches in 
length, and half an inch in breadth. 
They approach each other from 
above downwards, so as to leave a 
triangular space between them, in 
which the vasa deferentia are situ- 
ated. When fully dissected out, 
each one is found to be from four 
to five inches in length. They are 
lined by mucous membrane, outside 
of which is a proper fibrous layer. 
They also receive a layer from the 
prostatic fascia, which attaches them 
to the bladder. Each one termi- 




The Posterior Aspect of 
THE Male Bladder; the se- 
rous COVERING IS REMOVED IN 

order to SHOW the Muscular 
Coat.— 1. The body of the blad- 
der. 2. Its fundus. 3. Its in- 
ferior fundus or base. 4. The 
tirachus. 5, 5. The ureters. 6, 6. 
The vasa deferentia. 7, 7. The 
vesiculse seminales. 



nates in a short tube, the ductus 



vesiculce seminalis. 

The Ductus Ejaculatoeius Com- 
munis, Fig. 181 (s), is about an inch 
in length. It passes forwards, up- 
wards, and somewhat inwards, be- 
tween the middle and lateral lobes 
of the prostate gland to open on 
the caput gallinaginis, in the floor of the prostatic portion of 
the urethra. At first the two ejaculatory ducts are a little 
distance apart, but lie close to each other in the latter part of 
their course. Their walls in the prostate gland are very 
thin, and some care is requisite to dissect them out entire. 

The Speematic Coed is composed of the vas deferens and 
the spermatic vessels and nerves. It extends from the back 



RELATIONS OF PELVIC VISCERA IN THE MALE. 435 

part of the testicle to the internal abdominal ring. The left 
cord is somewhat the longest. The spermatic artery is a branch 
from the aorta. It enters the testicle through the corpus 
Highmorianiim, and divides into numerous small branches, 
which ramify in the su.bstance of the gland. The spermatic 
veins commence in the testicle, and leave it in company with 
the artery. Just above the testicle they form a plexus named 
the plexus j^ampijiiforinis. They contain no valves. Those on 
the right side terminate by a single trunk in the ascending 
cava, and those on the left side in the renal vein. The nerves 
of the testicle are derived from the plexus which accompa- 
nies the spermatic artery. 



Eelations of the Pelvic Yiscera in the Male. 

The pelvic viscera of the male consist of the rectum, the 
bladder, the vesiculce seminales, and the prostate gland. The 
rectum occupies the posterior part, and the other organs the 
anterior part. 

In studying the relations of the rectum, it may be divided 
into two parts, the upper and loiver; the first being in direct 
relation with the peritoneum, and the last having no serous 
covering. 

The upp)er part, Fig. 187 (i e), extends downwards to the 
recto- vesical fascia, or to within about three-quarters of an 
inch of the prostate gland. The whole of this part is co- 
vered in front, and partly on the sides, by the peritoneum, 
and is in relation with the bladder, and usually with the 
small intestines ; the superior portion is also covered behind 
by peritoneum, except a small space between the laminae of 
the mesorectum. Below it is in apposition with the sacrum, 
the pyriform muscles, the branches of the internal iliac arte- 
ries, the sacral nerves, and the ureters, especially the one on 
the left side. 

The loiver part, Fig. 187 (i e), is in relation behind and on 
the sides with the sacrum and coccyx, and the coccygeus 
and levatores ani muscles. It has in front of it, commencing 
above, first, the vesicuh\3 seminales and the triangular space 
between them on the base of the bkuidcr; second, the pi*os- 
tate gland; third, the membranous portion o\^ the urethra 



436 



OF THE PELVIS. 



and tlie bulb. Some portions of the rectum are separated 
from the surrounding parts by a considerable quantity of 
adipose and areolar tissue. 

As tbe Bladdee, Fig. 187 (3,4, 5), varies in size according 
as it is empty or distended, its relations to contiguous parts 
are necessarily modified. Wlien empty, it is in relation an- 

Fig. 187. 




A Side View op the Viscera of the Male Pelvis, in sittt. The right side 
OF the Pelvis has been removed by a Vertical Section jiade through the 
Os Pubis near the Symphysis ; and another through the middle op the Sa- 
crum. — 1. The divided surface of the os pubis. 2. The divided surface of the 
sacrum. 3. The body of the bladder. 4. Its fundus; from the apex is seen 
passing upwards, the urachus. 5. The base of the bladder. 6. The ureter. 7. 
The neck of the bladder. 8, 8. The pelvic fascia; the fibres immediately above 
7 are given off from the pelvic fascia, and represent the anterior ligaments of the 
bladder. 9. The prostate gland. 10. The membranous portion of the urethra, be- 
tween the two layers of the deep perineal fascia. 11. The deep perineal fascia 
formed of two layers. 12. One of Cowper's glands between the two layers of deep 
perineal fascia, and beneath the membranous portion of the urethra. 13. The bulb 
of the corpus spongiosum. 14. The body of the corpus spongiosum. 15. The 
right crus penis. 16. The upper part of the rectum. 17. The recto-vesical fold of 
peritoneum. 18. The lower portion of the rectum. 19. The right vesicula serai- 
nalis. 20. The vas deferens. 21. The rectum covered by the descending layer of 
the pelvic fascia. 22. A part of the levator ani muscle investing the lower part of 
the rectum. 23. The external sphincter ani. 24. The interval between the deep 
and superficial perineal fascia ; they are seen to be continuous beneath the number. 
25. Peritoneum covering the upper and back part of the bladder. 

teriorly with the symphysis pubis, the pubic boneSj and obtu- 
rator muscles; and when distended, with the anterior walls 
of the abdomen. In the latter case, the peritoneum is raised 



RELATIONS OF PELVIC VISCERA IN THE MALE. 437 

up SO as to leave a non-peritoneal surface above the symphy- 
sis, when the bladder can be cut into for the purpose of re- 
moving calculi or evacuating its contents without injuring 
the peritoneum. It can also be perforated through the sym- 
physis. Posteriorly^ it is in contact, above, with the rectum 
and with the small intestines, and, when iilled, with the sig- 
moid flexure of the colon ; below, with the vesiculse semi- 
nales, the vasa deferentia, and the rectum. Sometimes, and 
especially when empty, the recto- vesical cul-de-sac extends 
down to the prostate gland and interposes between the vesi- 
cal triangle and the rectum. It is through this triangular 
space that the bladder is sometimes perforated from the 
rectum. When this operation is performed it should be 
done close to the prostate gland to avoid the peritoneum, 
and in the median line, so as not to injure the vesiculas 
seminales and the vasa deferentia. Laterally^ the bladder is 
in relation on each side above, with the remains of the 
hypogastric artery and the vas deferens; and below, with 
the levator ani muscle and the pelvic fascia. Its nech^ Fig. 
187 (7), is in apposition with the prostate gland. 

The bladder is retained in situ by ligaments, by fasciaa, 
and by the peritoneum. The ligaments of the bladder are 
designated the true and the false. The false consists simply 
of two folds of peritoneum, one on each side of the cul-de-sac 
between the bladder and the rectum; they are sometimes 
called the posterior ligaments of the bladder. The anterior 
true ligaments arise from the lower part of the pubic bones, 
and are inserted into the neck of the bladder. The lateral 
true ligaments are derived from the pelvic fascia, and will be 
described in connection with it. 

The Prostate Gland, Fig. 188 (2), is in relation, ahove^ 
with the anterior ligaments of the bladder; on the sides with 
the levatores ani, and below, with the rectum. It is from two 
to two and a half inches above the anus. Its base corre- 
sponds to the neck of the bladder and its apex to the mem- 
branous portion of the urethra. 

The relations of the membranous portion of the urethra 
and the bulb will be described in this place preparatory to 
the examination of the perineal lasciie. 

The MEMBRANOUS PORTION of the urethra. Fig. 187 (1 0), 
is situated beloAv the arch of the pubes and extends from the 

87-^ 



438 



OF THE PELVIS. 



prostate gland to the bulb. It is in front of the rectnm, from 
which it is separated by a triangular space, the base of which 
looks downwards and forwards towards the bulb and the pe- 



Fis. 188. 




AyTERO-POSTEEIOR SECTIOJT OT THE PeLTIS OF A MaLE, EXHIBITIXG THE YlSCERA 
I>- THEIR XaTURAL SitUATIOX, ASD THE CuRTATURES OF THE UrETHRA. — 1. The 

bladder. 2. The prostate. 3, 3. The urethra, laid open through its Trhole extent. 
4, The seminal vesicle, laid open. 5. The spongy body, seen both above and below 
the urethra. 6. The bulb of the spongy body. 7. The cavernous body of the penis. 
8. The right side of the scrotum. 9. The rectum. 10. The peritoneal lining of 
the abdominal muscles. 11. The peritoneal investment of the bladder. 12. Tho 
point where the peritoneum is reflected from the bladder upon the rectum. 13. 
The section of the pubic symphysis, li. A line maxking the situation of the tri- 
angular ligament. 

rineal centre ; the apex is directed upwards and backwards 
to the point where the prostate gland rests against the rec- 
tum. It is about an inch below the symphysis, from which 
it is separated by an elastic and spongy structure, the mus- 
cles of Gruthrie and TTilson, and the deep perineal fascia. 

The BULB of the corpus spongiosum, Fig. 187 (i s), corre- 
sponds to the upper part of the pubic arch, and is anterior 
to the ti^i angular ligament. It is about three-foutrths of an 
inch in front of the rectum. It is covered below bv the in- 



DISSECTION OF THE VESSELS AND NERVES. 439 

tegument, the common superficial fascia, tlie superficial pe- 
rineal fascia, and tlie ejaculatores nrinse muscles. 



Dissection of the Vessels and Nerves in the Pelvic 

Cavity. 

The principal vessels and nerves in the pelvic cavity can 
be examined without removing any portion of the bones 
that form its parietes ; to make a thorough dissection of them, 
however, the os innominatum on one side should be disar- 
ticulated and removed ; or any portion of it may be cut 
away, including any part of the sacrum that may be found 
necessary in the progress of the dissection. The saw, or a 
mallet and chisel may be used for this purpose. To trace 
the vessels which supply the bladder and rectum, these organs 
should be moderately distended, the former with air, and the 
latter with cotton or tow. If the arteries be well injected 
but little difficulty will be encountered after the peritoneum 
has been removed, in exposing all the principal branches, as 
far as the organs which they supply or the openings through 
which they leave the pelvic cavity. 

The Middle Sacral Artery seems to be a continuation of the 
aorta greatly diminished in size. It extends in the median 
line from the bifurcation of the aorta to the coccyx, passing 
over the body of the last lumbar vertebra and the sacrum. 
In its course it gives off small branches, some of which anas- 
tomose with the lateral sacral arteries, and others enter the 
meso-rectum. 

The Internal Iliac or Hypogastric Artery, Fig. 189 
(g). Fig. 190 (fi), furnishes most of the branches found in the 
pelvis. It arises from the bifurcation of the common iliac 
artery opposite the sacro-iliac symphysis, and descending 
into the pelvis terminates near the upper border of the great 
sacro-sciatic foramen. It varies in length from an inch to 
an inch and a half Near its origin it is separated from the 
peritoneum by the ureter. The lumbo-sacral nerve lies be- 
hind it ; tlie internal iliac vein is situated behind and a little 
to the outer side of it. In the foetus the internal iliac is 
continued to the umbilicus, where it becomes the umbilical 
artery. Commencing at the origin of the vesical artery a 



440 



OF THE PELVIS. 



ligamentous cord will be observed extending on the side of 
the bladder to the anterior parietes of the abdomen, and 
thence to the umbilicus ; this is the remains of the hj^po- 
gastric artery of the foetus. The folds of peritoneum formed 
by these fibrous cords, there being one on each side, were 
noticed in the examination of that membrane. The yasa 
deferentia pass over these cords. 

The branches of the internal iliac artery vary so much in 
their origin that no fixed rule, perhaps, need be observed in 
describing them. They will be noticed in the order in which 
it will be found most convenient to examine them in the dis- 
section. The internal iliac very frequently divides into two 
principal trunks, from which the branches proceed. They 
•are designated the anterior and posterior divisions, Fig. 189 
(7, s). When this division exists, the latter usually gives off 

Fig. 189. 




A DIAGRAM OF THE Iliac Arteries axd THEIR BRANCHES. — 1. The aorta. 2. 
The left common iliac artery. 3. The external iliac. 4. The epigastric artery. 5. 
The internal circumflex ilii. 6. The internal iliac artery, 7. Its anterior division. 
8. Its posterior division. 9. The umbilical artery giving off (10) the superior vesical 
artery. After the origin of this branch the umbilical artery becomes converted 
into a fibrous cord — the umbilical ligament. 11. The internal pudic artery passing 
behind the spine of the ischium (12) and small sacro-sciatic ligament. 13. The 
middle hemorrhoidal artery. 14. The sciatic artery, also passing- behind the 
small sacro-sciatic ligament to escape from the pelvis. 15. Its inferior vesical 
branch. 16. The iliolumbar, the first branch of the posterior division (8) ascend- 
ing to anastomose with the internal circumflex ilii artery (5), and form an arch 
along the crest of the ilium. 17. The obturator artery. 18, The lateral sacral. 19. 
The gluteal artery escaping from the pelvis through the upper part of the great 
eacro-sciatic foramen. 20. The sacra media. 21. The right common iliac artery 
cut short. 22. The femoral artery. 



DISSECTION OF THE VESSELS AND NEEVES. 441 

the gluteal, tlie ilio-lumbar, and the lateral sacral, while the 
former supplies the remaining branches or arteries. 

The ilio-lumbar artery^ Fig. 189 (le), arises from the back 
part of the internal iliac, near its origin, passes outwards be- 
hind the external iliac artery and vein and the psoas mag- 
nus, to divide into a lumbar and an iliac branch. The former 
passes upwards, and sends off branches to the psoas and 
quadratus lumborum muscles, to the spinal canal, and to 
anastomose with the last lumbar artery. The latter passes 
downwards and outwards as far as the crest of the ilinm, 
.where it anastomoses with the internal circumflex ilii ; some- 
times it is found ramifying in the iliacus internns muscle, or 
beneath it on the surface of the bone. By means of this 
artery an anastomotic connection is established between the 
internal and external iliac arteries. 

The obturator artery^ Fig. 189 (i 7), not "unfrequently has its 
origin from some other than the internal iliac arterj^, as the 
external iliac, the epigastric, or the femoral. The course it 
takes to reach the inner part of the thigh will vary with its 
origin. When it arises from the internal iliac it passes hori- 
zontally forwards just below and on the inner side of the 
brim of the pelvis to the sub-pubic groove in the upper border 
of the obturator foramen. The obturator nerve lies above 
it, but follows the same course. "When it arises from either 
of the other arteries mentioned above, it passes inwards over 
the brim of the pelvis, to enter the sub-pubic groove. AYhen 
it has its origin from the femoral artery, however, it first 
passes upwards through the femoral ring, and then inwards. 
Its relations to the femoral ring are noticed in connection 
with the anatomy of femoral hernia. It usually gives off 
several smaU branches in the pelvis, in its course to the 
thigh ; the most important of which is a branch that anas- 
tomoses with the epigastric; sometimes this is quite large, 
and deserves special notice from its relation to femoral 
hernia. Having passed through the obturator foramen, the 
obturator artery divides into two principal branches, an 
internal and external. These are distributed to the muscles 
on the inner and back part of the thigh. The external 
division sends a small branch through the notch at the lower 
part of the acetabulum to supply the hip-joint; by means of 
the ligamentum teres the head of the foiuur is partly supplied 
from this brancli. 



442 



OF THE PELVIS. 



Fig. 1 90. 




WM 



{^\'f 



The vesical arteries^ Fig. 190 
(ii), consist of two principal 
brandies, a swperior and an in- 
ferior. The former is usually a 
continuation of that part of the 
hypogastric artery in the foetus, 
which, instead of being con- 
verted into a ligamentous cord, 
remains pervious after birth. 
It ramifies on the back, sides, 
and fundus of the bladder; 
sometimes a branch extends 
upwards from the summit to- 
wards the umbilicus. The latter^ 
or vesico-prostatic^ commonly 
arises directly from the internal 
iliac, and is distributed to tbe 
neck and lower part of the 
bladder, to the prostate gland, 
to the corresponding seminal 
vesicle, and the upper part of 
the urethra. A small branch 
is sent to the vas deferens, 
named the deferential artery; 
also another one to the ureter. 
The inferior artery of the blad- 
der varies very much in its 
origin. Besides these branches 
the bladder is generally suppli-' 
ed w^ith several small branches 
derived from other sources. 



Thk Arteries of the Pelvis and' Thigh, as seex from the Inxer Side, by 
A Vertical Section. — 1. Inferior extremity of the abdominal aorta, just where 
it divides into the iliac arteries. 2. Right primitive iliac. 3. Right external iliac. 
4. Origin of epigastric artery. 5. Internal eircumflex ilii. 6. Hypogastric or internal 
iliac artery. 7. Ilio-lumbar. 8. Gluteal. 9. Obturator. 10. Lateral sacral. 11. 
Vesical arteries cut off. 12. Middle hemorrhoidal. 13. Internal pudic. 14. Ischi- 
atic, 15. Commencement of the femoral artery at the crural arch. 16. Point 
where it passes through the adductor magnus. 17, 20, 21. Arteria profunda. 18. 
Internal circumflex. 19, 19, 19. First, second, and third perforating arteries. 22. 
A branch to the vastus internus. 23. Femoral artery passing through the canal 
formed by the tendon of the adductor magnus. 24. The anastomotica. 25. A 
branch to the sartorius muscle. 26. Popliteal artery. 27. The same artery be- 
hind the knee-joint under the soleus muscle. 28. A supernumerary articular 
artery. 29. Superior internal articular artery. 30. Inferior internal articular 
artery. 31. Anastomosis of the three last with anastomotica. 



DISSECTION OF THE VESSELS AND NERVES. 443 

The middle hemorrhoidal artery, Fig. 190 (12), arises from 
the internal iliac, scftietimes from the inferior vesical or the 
internal pndic, passes to the side of the rectum, where it 
anastomoses with the superior and inferior hemorrhoidal 
arteries. It is very irregular in its origin, and sometimes is 
absent. 

The uterine artery arises from the internal iliac, and, pass- 
ing between the layers of the broad ligament, reaches the 
uterus just above the os tincae. It then ascends on the bor- 
der to the fundus, giving off branches in its course, which 
ramify on the anterior and posterior surfaces of the uterus ; 
some of these penetrate its substance, others anastomose in the 
median line with the corresponding branches on the opposite 
side. It sends small branches to the bladder and u.reters. 
During the period of pregnancy, the uterine arteries attain 
to a great size, and become exceedingly tortuous. 

The ovarian arteries anastomose freely with the uterine. 
They arise from the aorta, and pursue a course downwards 
similar to that of the spermatic arteries in the male until 
they reach the brim of the pelvis, when they are directed 
inwards to get between the layers of the broad ligaments. 
Each one penetrates the ovary at its attached border. In 
their course to the ovaries they are very much convoluted. 
They send branches to the Fallopian tubes and to the round 
ligaments; the latter branches accompany the Fallopian 
tubes to their destination. 

The vaginal artery arises in common with the inferior 
vesical, or from the hypogastric, just before or after that 
artery. It passes downwards on the side of the vagina to 
near its external orifice, when it gets behind it, between the 
vagina and rectum, to anastomose with branches from the 
opposite side. It sends branches in its course to the bladder 
and the urethra, also to the rectum. 

The lateral sacral arteries^ Fig. 190 (1 0), usually consist of 
two, a superior and inferior, on each side. They arise close 
to each other just above the gluteal. The superior passes 
downwards and inwards to the first sacral foramen, which it 
enters to reach the sacral canal, where it divides into two 
branches; one of these escapes from the canal through the 
corresponding posterior sacral foramen, and is distributed to 
the muscles and integument of the back, while the other 
ramifies in the canal. The inferior descends in front of the 



444 OF THE PELVIS. 

pyriformis muscle and sacral nerves and on the inner side 
of the anterior sacral foramina to the si^ of the coccyx. It 
gives off small branches which enter the sacral foramina, 
and have each one of them the same distribution as the 
superior lateral sacral artery. Besides the branches which 
enter the sacral canal, these arteries give off branches that 
anastomose with the middle sacral artery and ramify on the 
anterior surface of the sacrum ; and also others which go to 
the pyriformis muscle and the sacral nerves. 

The gluteal artery^ Fig. 190 (s), from its size, might be 
regarded as a continuation of the internal iliac. It escapes 
from the pelvis at the upper part of the great sacro-sciatic 
foramen between the gluteus medias and pyriformis muscles. 
In its course downwards and backwards it passes between 
the lumbo-sacral and the first sacral nerve. In the pelvis it 
gives off a nutritious branch to the ilium and one or more 
muscular branches. Having escaped from the pelvis it divides 
into a superficial and a deep branchy which will be noticed in 
the dissection of the gluteal region. 

The sciatic or ischiatic artery^ Fig. 190 (14), varies in its 
origin. Not unfrequently it arises in common with the in- 
ternal pudic, from which it does not separate until just before 
it leaves the pelvis. It passes downwards in front of the 
pyriformis muscle and sacral plexus of nerves to the lower 
part of the great sacro-sciatic foramen, where it is placed 
between the pyriformis and superior gemellus muscles, having 
the great sciatic nerve on the inner side of it and the internal 
pudic artery behind it. It gives off in its course in the 
pelvis the coccygeal branch, which perforates the great sacro- 
sciatic ligament and ramifies on the dorsum of the coccyx. 
As it leaves the pelvis, it sends off a branch named the comes 
nervi ischiadici to accompany the great sciatic nerve. Its 
course and distribution outside the pelvis will be examined 
in the dissection of the gluteal region and upper and back 
part of the thigh. 

The internal pudic artery^ Fig. 190 (1 3), has the same direc- 
tion and relations in the pelvis as the sciatic artery, which it 
accompanies to the spine of the ischium, around which it 
winds to enter the perineum. Its course and branches in 
the perineum will be observed in the dissection of that 
region. It is in some respects the most important branch 
given off' from the internal iliac, to be studied. This is 



DISSECTION OF THE VESSELS AND NERVES. 445 

owing to its liability to injury in cutting for stone and 
in other operations in the perineum. Before it leaves the 
pelvis it supplies branches to the levator ani muscle, the 
rectum, the bladder, the vesiculas seminales, and to the pros- 
tate gland. Its distribution in the female differs from that 
in the male. While within the pelvis in the female, besides 
sending branches to the bladder and rectum, it sends branches 
to the vagina; in the perineum the branches that correspond 
to those which go to the penis in the male are distributed to 
the clitoris. 

The INTERNAL ILIAC VEIN IS placed on the inner side of 
the internal iliac artery with which it corresponds. It re- 
ceives the blood from the veins that accompany the branches 
of the internal iliac artery, and also from the vesico-prostatio 
plexus, including that portion of the blood contained in the 
hemorrhoidal plexus which does not find its way to the infe- 
rior mesenteric vein and thence to the portal vein. It has 
no valves. It is exceedingly important that every student 
should thoroughly understand the plexuses of veins con- 
nected with the rectum and genito-urinary apparatus. It 
will be seen that a part of the blood from these plexuses 
reaches the heart through the internal and common iliac 
veins and the vena cava, while another portion passes 
through the mesenteric and portal veins to the liver, and 
thence through the hepatic veins and vena cava to the heart. 
Each artery has its venae comites, which unite to open into 
their main trunk by a common orifice. 

The ilio-lumbar vein opens into the common iliac. It is 
united to the veins which escape from the spinal canal 
through the lower lumbar intervertebral foramina ; also to 
a vein which lies in front of the last lumbar vertebra, and to 
the lateral sacral veins by an anastomosing branch. 

The middle sacral and the lateral sacral veins correspond to 
the arteries of the same names. The former arises in front 
of the coccyx, and passes iipwards to terminate in the left 
common iliac vein. Not unfrequently a communicating 
branch is found connecting this vein with the hemorrhoidal 
plexus, and also with the vesical plexus. The latter consist 
of two or more veins, which open into the common iliac 
vein. 

The veins which accompany the gluteal, the sciatic, the 
38 



446 OF THE PELVIS. 

obturator, and the internal pndic artery, require no particular 
description. 

The hemorrhoidal veins and plexus are situated in the pa- 
rietes of the lower part of the rectum. Thej consist of the 
superior, middle, and inferior hemorrhoidal veins, which 
empty, the superior into the inferior mesenteric, and the mid- 
dle and inferior into the internal iliac vein, or a branch of it. 
A venous network is found just beneath the mucous mem- 
brane, and close to the anus. Hemorrhoids are very fre- 
quently caused by the dilatation of the veins that form this 
network or plexus, as was noticed in the dissection of the 
rectum. 

The vesico -prostatic plexus, Fig. 199 (9), is situated in the 
upper pouch or pocket formed by the deep perineal and pel- 
vic fasciae, by which the veins that form a portion of the 
plexus are prevented from becoming very much distended. 
It covers the prostate gland and the neck of the bladder. 
In cutting for stone, this plexus is necessarily more or less 
wounded, which may give rise to a good deal of hemorrhage, 
the amount depending on the condition of the veins at the 
time of the operation. Behind, it communicates with the 
hemorrhoidal plexus; in front and below with the veins 
which surround the membranous portion of the urethra ; it 
also receives the contents of the dorsal veins of the penis. 
These veins, after passing through the sub-pubic ligament 
and deep perineal fascia, unite to form a single trunk, which 
divides these into a right and left vein, in order to join the 
prostatic plexus on both sides of the prostate gland. The 
veins from the dorsum of the penis are kept constantly open 
where they perforate the dense fibrous structure of which the 
sub -pubic ligament and deep perineal fascia are composed. 
They also communicate freely with the deep veins, or those 
which accompany the branches of the internal pudic artery. 

The spermatic veins were noticed in the dissection of the 
testicle. They communicate with the dorsal veins of the 
penis, and with the pudic veins. There is occasionally a 
communication existing between the spermatic vein and the 
portal system. 

The ovarian veins are formed by branches derived from the 
uterus, the ovaries, and the Fallopian tubes. They accom- 
pany the ovarian arteries, and have the same termination as 
the spermatic veins. 



DISSECTION OF THE VESSELS AND NERVES. 447 

The vaginal plexus of veins surrounds the vagina. Near 
the vulva the plexus is composed of a great number of veins, 
many of which have their origin in the erectile tissue that is 
found around the external orifice of the vagina. The veins 
of the vaginal plexus communicate behind, with the hemor- 
rhoidal plexus, and before, with the vesical plexus. 

The uterine veins correspond on the exterior surface of the 
uterus to the uterine arteries. They arise from venous canals^ 
or sinuses^ which traverse the substance of the uterus, without, 
however, being tortuous like the arteries. The veins, as 
well as the arteries of this organ, increase greatly in size 
during the period of pregnancy. 

The nerves which supply the pelvic viscera are derived 
from the lumbo-sacral, the anterior sacral, and the sympa- 
thetic system. 

Besides the visceral nerves, there are several small branches 
derived from the sacral nerves or plexus, and appropriated to 
the muscles within the pelvis and perineum. There is also 
found in the pelvis a branch from the lumbar plexus called 
the obturator nerve^ which from its position should be exa- 
mined first. 

The obturator nerve, Fig. 191 (e), arises from that portion 
of the lumbar plexus which is formed by the third and fourth 
lumbar nerves. To reach the pelvis, it first passes through 
the psoas magnus muscle, and then runs for some distance on 
its inner side; it then crosses over the brim of the pelvis, 
and gets below the external iliac vein and above the obtura- 
tor artery, which it accompanies to the sub-pubic groove, 
when it enters the upper and inner part of the thigh. After 
perforating the psoas muscle, it passes beneath the bifurca- 
tion of the common iliac vessels. In the pelvis, near the 
obturator foramen, it usuall}^ gives off one or two articular 
branches to the hip-joint. As it enters the thigh it divides 
into the superficial or anterior division, and the deep or posterior 
division. These are distributed principally to the muscles on 
the inner part of the thigh, and will be noticed in the dis- 
section of that reo'ion. 

o 

When the obturator accessory nerve, Fig. 191 (5), is present, 
and of its usual size, it supplies the hip-joint with articular 
filaments instead of the obturator nerve itself The accessoiy 
nerve has the same origin as the obturator nerve; of which 
it is sometimes a part for a short distance, when it becomes a 



448 



OF THE PELVIS. 



separate nerve. It perforates the psoas muscle, and descends 
on its inner side to the pubes, which it passes over on the inner 
side of the ilio-pectineal eminence to get beneath the pecti- 
neus muscle, where it gives off its articular filaments to the 
hip-joint and divides into several other branches; one of 
which descends as low as the upper and back part of the leg, 
sending in its course a filament to the knee-joint. 

The superior gluteal nerve^ Fig. 192 (2), may be examined 
next. It arises from the lumbo-sacral before it joins the first 

sacral nerve to become a 



Fig. 191. 



part of the sacral plexus. 
It escapes from the pelvis 
in company with the glu- 
teal artery through the up- 
per part of the great sacro- 
sciatic foramen, above and 
in front of the pyriformis 
muscle, and divides into 
two branches which cor- 
respond in their distri- 
bution with the gluteal 
artery. It supplies the 
gluteus medius, minimus, 
and tensor vaginae femoris 
muscles. 

The lumho-sacral nerve^ 
rig. 192.(i); is formed by 
the union of the descend- 
ing portion of the fourth 
lumbar, and the fifth lum- 
bar. It enters the pelvis, 
and assists in forming the 
sacral plexus. 

There are six anterior 
sacral nerves, including 
what is sometimes called 



The Lumbar Plexus and its Branches (slightly altered from Schmidt). — 
a. Last rib. h. Quadratus lumborura muscle, c. Oblique and transverse muscles, 
cut near the crest of the ilium, d. Os pubis, e. Adductor brevis muscle. /. Pec- 
tineus. g. Adductor longus. 1. Superior musculo-cutaneous branch. 2. Middle 
musculo-cutaneous branch. 3. Inferior musculo-cutaneous branch. 4. Anterior 
crural nerve. 5. Accessory obturator. 6. Obturator nerve. 7. Genito-crural nerve 
dividing into two at its origin from the plexus. 8, 8. Gangliated cord of the 
sympathetic nerve. ~ 




DISSECTION OF THE VESSELS AND NERVES. 449 

the coccygeal nerve. Thej escape from the sacral or lower 
part of the spinal canal, through the anterior sacral foramina. 

The first and second nerves are quite large, and of nearly 
the same size. The first being joined by the lumbo-sacral, 
passes obliquely downwards over the pyriformis muscle to 
the sacral plexus. The second nerve proceeds more obliquely 
outwards than the first to join the plexus. 

The third nerve, as it goes to join the sacral plexus, has a 
still more oblique direction, being nearly horizontal. It is 
only about one-fourth the size of the first and second nerves. 
To the latter nerve it is connected by a filament, which will 
be seen passing over the pyriformis muscle. 

The fourth nerve is very much smaller than the third. A 
part of it only goes to join the sacral plexus. The rest of it 
sends branches to join the hypogastric plexus of the sym- 
pathetic nerve, one to join the fifth nerve, and others to 
supply the levator ani, the coccygeus and sphincter ani 
muscles. 

The fifth nerve usually passes through the foramen formed 
by the sacrum and coccyx. It is much smaller than the 
fourth, to which it is joined by a communicating branch; it 
sends a branch to the sixth nerve. 

The sixth sacral or the coccygeal nerve is generally very 
small ; it emerges at the lower end of the spinal canal ; from 
which point it should be traced. 

It will be observed that of the sacral nerves only the first 
three, and a part of the fourth, contribute to form the sacral 
plexus. Each one of them is joined to a ganglion of the 
sympathetic nerve by a communicating branch; they are 
also connected to each other by a similar branch. 

The Sacral Plexus, Fig. 192 (4), is formed, as has been 
seen, by the union of four whole nerves and portions of two 
others. The whole nerves are the last lumbar and the first 
three sacral; the parts are derived from the fourth lumbar 
and the fourth sacral nerve. The shape of the plexus is tri- 
angular; its base looks towards the foramina through which 
the nerves that form it escape from the spinal canal, while 
its apex corresponds to the beginning of the great sciatic 
nerve, which is close to the lower part of the great sciatic 
foramen through which this nerve n^akes its exit from the 
pelvis. 

38* 



450 



OF THE PELVIS. 



The sacral plexus is more simple in its structure tlian any 
other belonging to the spinal system of nerves. 

The plexus lies on the anterior surface 
Fig. 192. of the pyriformis muscle ; in front, it cor- 

responds to the lower part of the rectum, 
from which it is separated by a fascia and 
branches of the internal iliac vessels. In ex- 
posing the sacral nerves and plexus, much 
care is requisite to preserve the nerves 
which arise from them, and which should 
now be traced to their destination if they 
end in the pelvis, and to their exit from the 
pelvis if thev go to supply parts outside 
of it. 

To do this no specific directions can be 
given, as they vary so frequently in their 
origin and general arrangement; this is 
more particularly the case with the nerves 
which supply the viscera. These may 
arise partly from the second and third 
nerves, or partly from the plexus, or al- 
most wholly from the fourth and fifth 
nerves. They may go in part directly to 
the viscera which they supply, as the rec- 
tum, the bladder, and the prostate gland, 
in the male ; and, in the female, to the blad- 
der, the uterus, the vagina, and the rectum ; 
or they may, some of them at least, join 
filaments of the sympathetic nerve, as the 
hypogastric plexus, and, in company with 
them, reach the same organs. As they are so 
iii \^>C^?^^ intimately connected with the hypogastric 

plexus and the filaments derived from it, 
the two sets of nerves should be examined 



A Diagram SHOwrjfGTHE Formation axd Branches of the Sacral Plexus.— 
1. The lumbo-sacial nerve, descending to join the sacral plexus, and giving off a 
large branch. 2. The superior gluteal nerve. 3. The anterior branches of the four 
upper sacral nerves. 4. The sacral plexus. 5. The internal pudic nerve. 6. The 
lesser sciatic nerve. 7. The great sciatic nerve. S. The peroneal nerve. 9. The 
popliteal nerve. 10. Its sural branches. 11. The posterior tibial nerve dividing 
inferiorly into the two plantar nerves, 12. 13. The anterior tibial nerve. 14. The 
musculu-cutaneous nerve, its muscular portion. 15. Its cutaneous portion. 16. 
The external saphenous nerve, formed by the union of the communicans poplitei, 
and communicans peronei. 



DISSECTION OF THE VESSELS AND NERVES. 451 

together; they will be referred to again in the dissection of 
the sympathetic nerve in the pelvis. 

Although a knowledge of these nerves possesses but little 
value as applied to surgical operations, its value cannot be 
estimated when viewed in connection with injuries and dis- 
eases in which the pelvic organs, either in the male or female, 
are directly or indirectly involved. 

The following are the muscular nerves derived from the 
sacral plexus or nerves and distributed principally to the 
muscles in the pelvis and perineum. 

The nerve to the pyriformis^ generally, comes from the pos- 
terior aspect of the plexus, but sometimes it proceeds from 
one of the sacral nerves before it enters the plexus ; some- 
times there are two of these small nerves, or one which di- 
vides it into two branches before penetrating the muscle. 

The nerves to the levator ani are usually two branches of the 
fourth sacral nerve. Besides these, this muscle commonly 
receives two or three filaments from the vesical and hemor- 
rhoidal nerves. The first of these nerves, or those from the 
fourth sacral nerve, penetrate the pelvic surface of the mus- 
cle, the largest one near its centre and the other near its 
anterior border. 

The nerve to the ohturator internus proceeds from the upper 
and anterior portion of the sacral plexus, passes around the 
spine of the ischium and through the small sacro-sciatic fora- 
men, when it divides into two or three branches which spread 
out and penetrate the inner surface of the muscle. 

The inferior hemorrhoidal nerve arises from the posterior 
part of the sacral plexus near the internal pudic, or from 
the internal pudic itself, which it accompanies through the 
small sacro-sciatic foramen to near the upper border of the 
sphincter ani muscle, where it divides into several small 
branches. Some of these penetrate the muscle at diflterent 
points, while others proceed to the integument around the 
anus; others still pass forwards and anastomose with the 
superficial perineal nerve and the perineal branch of the 
lesser sciatic nerve. The inferior hemorrhoidal nerve corre- 
sponds in its distribution with the artery of the same name. 
The sphincter ani is also supplied in part by filaments which 
proceed to it directly from the fourth and fiftli sacral nerves; 
and also from the internal pudic. And again, the inferior 



452 OF THE PELVIS. 

hemorrlioidal nerve is occasionally wholly cutaneous, sending 
no filaments to the sphincter muscle. 

The coccygeus muscle is supplied with filaments derived 
from the fourth and fifth sacral nerves, and the coccygeal 
nerve. One or two of these nerves, after perforating the 
coccygeus muscle, become cutaneous, and supply the integu- 
ment behind the anus and on the back of the coccyx. 

Two small nerves usually arise from the sacral plexus 
"which are distributed to the gemdli and quadyratus femoris 
w-usdes^ and also to the hip-joint. The one that supplies the 
superior gemellus arises from the plexus near the origia of 
the internal pudic. The one that goes to the inferior ge- 
mellus and quadratus femoris arises from the plexus at or 
near the commenqement of the great sciatic nerve, passes 
downwards behind the superior gemellus and obturator in- 
ternus muscles, between them and the capsule of the hip- 
joint, to reach the deep surface of the muscles to which it is 
distributed. Besides supplying these muscles, this nerve 
sends filaments to the hip-joint. 

The internal pv.dic or superior long pudendxil nerve arises 
from the lower part of the sacral plexus, and soon joins the 
internal pudic artery which it accompanies through the small 
sacro-sciatic foramen to the perineum, where it divides into 
two terminal branches, named the jjerineoJ. nerve and the dor- 
sal nerve of the penis. They will be noticed as they are met 
with in the dissection of the parts to which they are distri- 
buted. It may be well, however, to give a brief description 
of the course and distribution of the branches of the internal 
pudic nerve in this place. 

The perineal nerve accompanies the internal pudic artery as 
far as a point nearly opposite to the junction of the tube- 
rosity and ramus of the ischium. At this place it perforates 
the obturator fascia, which up to this point in the perineum 
separated it from the ischio-rectal fossa, and divides into its 
two terminal branches. One of these, named the superficial 
jyerineal nerve, Fig. 195 (2), corresponds to the superficial pe- 
rineal artery. It is placed in the groove between the erec- 
tor penis and accelerator urin^e muscles, and is distributed to 
the scrotum, some of its filaments being continued forwards 
to the integument covering the under surface of the penis. 
The other branch passes above the trans vers as perinei mus- 
cle and sends filaments to the accelerator urin^B, to the bulb 



DISSECTION OF THE VESSELS AND NERVES. 453 

of the corpus spongiosum, and to tlie muscles of "Wilson 
and Guthrie. 

The perineal nerve, just before it enters the perineum, gives 
ofi' a branch which has been called the posterior superficial 
perineal nerve. It perforates the great sacro-sciatic ligament, 
enters the ischio-rectal fossa, and passes forwards to be distri- 
buted to the scrotum in the male, and to the vulva in the 
female. It anastomoses with the inferior hemorrhoidal and 
the perineal branch of the small sciatic nerve; and some- 
times sends branches to the sphincter ani and coccygeus 
muscles. 

The dorsal nerve of the penis ^ instead of perforating the 
obturator fascia, continues forwards, gets between the layers 
of the deep perineal fascia, perforates the anterior one, and 
reaches the dorsum of the penis in company with the artery 
of the same name. It proceeds forwards to the glans penis, 
to which it is distributed. It gives off a cutaneous branch 
which divides into numerous filaments to supply the skin 
including the prepuce; it also sends off branches which 
penetrate the substance of the corpus cavernosum. The cor- 
responding nerve of the one last described, in the female, 
is distributed to the clitoris. 

The small or lesser sciatic nerve^ Fig. 192 (e), arises from the 
lower part of the sacral plexus by one, and sometimes by 
several nervous cords. It leaves the pelvis at the lower part 
of the great sacro-sciatic foramen, and beneath the pyriformis 
muscle. At first it is placed on the inner side of the great 
sciatic nerve, but soon gets behind it. It divides into mus- 
cular and cutaneous branches. The former supply the glu- 
teus maximus; the latter are divided into the external and 
internal ; they are distributed to the skin on the outer, back 
and inner parts of the thigh, one or tAvo branches descending 
as low as the upper part of the leg. Another branch, 
named the perineal cutaneous^ or the inferior long pudendal 
nerve, Fig. 218 (4), passes downwards and inwards below the 
tuber iscliii to reach the anterior part of the perineum, where 
it divides into two branches, Avhich pass forwards, one on 
each side of the testis, to be distributed to the anterior part 
of the scrotum, and to the skin on the under part of the 
penis. It anastomoses with the superficial perineal nerve. 

The great sciatic nerve, Fig. 192 (7), is the terminal branch 
of the sacral plexus. It escapes from the pelvis through the 



454 OF THE PELVIS. 

lower part of the great sacro-sciatic foramen ; sometimes a 
portion of it pierces the pyriformis mnscle. It will be exa- 
mined in the dissection of the back part of the pelvis and 
thigh. 

The sympathetic nerve. Fig. 142, presents in the pelvis 
several ganglia and plexuses. The ganglia are placed to the 
inner side of the anterior sacral foramina. They consist 
usually of five on each side. The upper one receives one, 
and sometimes two communicating branches from the last 
lumbar ganglion. The lower one on each side is connected 
by a filament to a single ganglion, called the ganglion impar ; 
this is situated in front of the coccyx. The ganglia of each 
side are connected by communicating filaments to the sacral 
nerves, there being two for each ganglion and its correspond- 
ing nerve ; they are quite short. 

There are two hypogastric plexuses in the pelvis, between 
which there is no direct communication. They are formed 
by a division of the lumbo-aortic plexus into two, a right 
and left. They are placed upon the sides of the principal 
organs in the pelvis, both in the male and female. They 
receive filaments from several sources in the pelvis, as the 
sacral ganglia, the inferior mesenteric plexus, and the ante- 
rior sacral nerves. Small ganglia are found where the sacral 
nerves unite with those of the plexus. Each hypogastric 
plexus gives off several plexuses ; they are the following : — 

The vesical plexus is situated on the side and lower part of 
the bladder. It sends off two sets of nerves ; the ascending, 
which supply the ureters and the upper part of the bladder 
both in front and behind; and the horizontal, which go to the 
lower part of the bladder, including the neck. Some of 
these continue over the prostate gland, forming the prostatic 
plexus. From these plexuses small filaments penetrate the 
structure of the bladder and prostate gland. 

From the side of the bladder and the ureter, nerves go to 
the vas deferens and to the vesicula seminalis, forming a 
plexus for each one of these organs. From the prostatic 
plexus nerves proceed to the urethra and to the spongy 
structure of the penis. They reach the dorsum of the penis 
by passing through the sub-pubic ligament. 

The rectum is supplied by the superior and middle hemor- 
rhoidal plexuses. The former comes from the inferior mesen- 
teric, the latter from the hypogastric plexus. These plexuses 
are intimately blended with each other. 



DISSECTION OF THE PERINEUM. 455 

An ovarian plexus accompanies eacli of the ovarian arteries 
from the abdomen ; the ovaries receive filaments also from 
the nterine nerves. 

The uterine nerves are derived from the hypogastric plexus. 
They accompany the arteries as they ascend on the lateral 
borders of the uterus, to supply its fundus anteriorly and 
posteriorly. From the neck of the uterus nerves proceed to 
the vagina to form the vaginal plexus. 



Dissection of the Peetneum. 

The outlines of the perineal space are indicated by the 
boundaries of the lower strait of the pelvic cavity. These 
consist, in front, of the sub-pubic ligament, the descending 
rami of the pubic bones and the rami of the ischia; late- 
rally, of the tuberosities of the ischia; and behind, of the 
sacro-sciatic ligaments and the coccyx. The student should 
make himself perfectly familiar with the exact position of 
each one of these parts before he attempts the examination 
of this region; or he should have a ligamentous pelvis before 
him when he makes his first dissection of the perineum. He 
should also have a distinct idea of the position and relations 
of the following parts: The lower part of the rectum, the 
bladder, the prostate gland, the membranous portion of the 
urethra, and the deep periaeal fascia or triangular ligament 
through which it passes, the bulbous portion of the corpus 
spongiosum, the crura of the corpora cavernosa, and the 
principal muscles in this region. If he cannot acquire this 
knowledge by reading a description of these parts A\^ith the 
aid of plates, he should make a special dissection of them. 
No student should expect to obtain a satisfactory knowledge 
of the anatomy of the perineum by making a single dissec- 
tion of it. When he has become familiar with the parts 
enumerated above, he will find that the study of the fiisciie 
involved in the dissection will be greatly facilitated. He 
will observe that every reflection or attachment of the fascii\3 
has a distinct relation to some one or more of these parts ; 
that they are designed to furnish a floor to the cavity of the 
pelvis, and to fix and keep the parts in their absolute and 
relative position. It will also be noticed in the progress of 
the dissection that they form the boundaries of several spaces 



456 OF THE PELVIS. 

whicTi are exceedingly interesting when viewed in reference 
to tlie formation of sinuses and abscesses, to effusions of 
urine, and to the dangers attending operations for the 
removal of calculi from the bladder, or for any other pur- 
pose. The great importance of a knowledge of the anatomy 
of the perineum should be impressed on the mind of every 
student independently of the idea of his ever being called 
upon to operate for calculi in the bladder. Yery few in the 
profession ever have an opportunity to cut for stone, while 
every physician is liable to meet with cases of sinuses, 
abscesses, and fistulous openings in this region, which he 
should be able to treat properly. 

To dissect the perineum, the subject must be placed on 
the back near the end of the table, with a small block 
under the pelvis. The thighs must be flexed and separated 
from each other; to keep them in this position, the feet 
may be fastened by a roller or a cord to the wrists ; or a cord 
may be attached to one of the thighs near the knee, car- 
ried under the table and fastened in the same manner to 
the opposite thigh. If a cord of suflQ.cient length be used, 
with blocks to support the thighs, the student will have no 
di£S.culty in placing and keeping the subject in a favorable 
position for making his dissection. The rectum, should be 
thoroughly washed out and moderately and evenly distended 
with tow, cotton, or a piece of a roller gradually introduced 
into it. The scrotum should be drawn upwards and fastened 
by hooks. 

The first thing to be done in the dissection is to remove 
the skin. To do this make an incision from the coccyx to 
the anus, and thence to the raphe of the scrotum ; and an- 
other from the nates on each side to the anus. In this way 
the integument may be raised in four flaps. The skin is so 
thin at the margin of the anus that some care is requisite to 
raise it and leave the superficial fascia. 

The common superficial fascia usually contains a large 
quantity of adipose substance, especially in the ischio-rectal 
fossce^ spaces situated, one on each side of the anus and lower 
part of the rectum. This fascia is continuous with the super- 
ficial fascia of the parts contiguous to the perineum, and 
must not be confounded with the superficial perineal fascia. 
To remove it the same incisions may be made as were made 
to raise the skin. Before doing this, however, the vessels 



DISSECTIOX OF THE PERINEUM. 457 

and nerves whicli ramify in it should be observed; also the 
houndaries of the ischio-rectal fossae. 

The arteries which, supply the perineum are derived prin- 
cipally from the internal pudic, a branch of the internal iliac 
artery. The course of this artery is deep seated, and will be 
noticed at an advanced stage of the dissection. The prin- 
cipal branches involved in the removal of the common 
superficial fascia are the inferior hemorrhoidal^ Fig. 194 (i o). 
These vary in number from one to three on each side. 
They pierce a layer of the obturator fascia which covers 
the internal pudic artery, and pass transversely, or nearly 
so, across the ischio-rectal fossa to the anus. They supply 
the lower part of the rectum, including the levator and 
sphincter ani muscles, and the integument around the anus. 
They are surrounded by the adipose substance which fills 
the ischio-rectal fossa. The student cannot be too particular 
in obtaining an accurate knowledge of the position of these 
vessels. The subcutaneous branches in the anterior part of 
the perineum are not of sufficient importance to require any 
special notice here. They consist of small branches of the 
superficial perineal artery^ which is also a branch of the in- 
ternal pudic, arising from it just after the hemorrhoidal are 
given off 

The veins correspond to the arteries and require no par- 
ticular notice. 

The nerves of the perineum are mainly supplied by the 
internal pudicj which enters this region in company with the 
internal pudic artery ; and its distribution is nearly the same 
as that of the artery. It sends hemorrhoidal branches to the 
lower part of the rectum, and to the levator and sphincter 
ani muscles. One of its principal divisions is called tlie 
superficial perineal nerve^ Fig. 195 {2)^ which passes forwards in 
company with the superficial perineal artery. In the anterior 
part of the perineum this nerve becomes subcutaneous and 
is distributed to the skin in that region and to the scrotum. 
A small branchy derived from the small sciatic nerve^ is also 
distributed to the integument of the perineum and scrotum; 
principally, however, to the latter. 

Before examining the boundaries and relations of the 
ischio-rectal fossoo, the sphincter ani and coccygcus muscles 
may be studied. 
39 



458 



OF THE PELVIS. 



The SPHINCTER ANI, Fig. 193 (s), is attached^ behind, by 
tendinous fibres to the coccyx ; anteriorly, to the subcuta- 

Fig. 193. 




A ViE-w OF THE Muscles of the PEEiNEtrM of the Male.— 1, 1. Rami of the 
ischia. 2, 2. Tuberosities of the ischia. 3. Posterior face of the coccyx. 4. Por- 
tion of the groat sacro-sciatic ligament. 5. Accelerator urinae. 6. Erector penis. 
7. Transversus perinei. 8. Sphincter ani. 9. Levator ani. 10. Musculus cocey- 
geus. IL Section of the gluteus maximus. 12. Adductor longus. 13. Adductor 
brevis. 14. Adductor magnus. 15. Gluteus maximus. 16. The urethra. 17,17. 
Corpora cavernosa turned up. 18. Spermatic cord turned up. 19. Eree extremity 
of the penis with its integuments. 



neons areolar tissue, and to a fibrous structure just in front 
of the anus, called the perineal centre^ to which the trans- 
versi perinei and the acceleratores urinas muscles are also 
attacbed. It surrounds the lower orifice of the rectum ; 
is narrow and somewhat pointed before and behind this 
opening, but an inch or more broad on each side of it. It 
presents an upper and a lower border. The lower one is 
separated from the skin by a very thin layer of areolar 
tissue, while the upper one is blended with, the fibres of the 
levator ani. The outer surface is in apposition with the adi- 
pose tissue contained in the ischio-rectal fossa. It closes the 
anus and at the same time slightly elevates it ; it also assists 
the trans versi perinei in fixing the perineal centre. 



DISSECTION OF THE PEEINEUM. 



459 



The COCCYGEUS, Fig. 193 (i o), is situated between the pyri- 
formis and the posterior border of the levator ani. It arises 
from the spine of the ischium and from the small sacro- 
sciatic ligament, and is inserted into the side of the coccyx 




The Arteries of the Perineum; on the Right Side the Superficial Arte- 
ries ARE SEEN, AND ON THE Lept THE Deep. — 1. The penis, Consisting of the corpus 
spongiosum and corpora cavernosa. The crus penis on the leftside is cut through. 
2. The acceleratores urinaa muscles, inclosing the bulbous portion of the cor})us 
spongiosum. 3. The erector penis, spread out upon the crus penis of the right side. 
4. The anus, surrounded by the sphincter ani muscle. 5. The rami of the ischi^um 
and pubes. 6. The tuberosity of the ischium. 7. The small sacro-sciatic ligament 
attached by its small extremity to the spine of the ischium. 8. The coccyx. 9. The 
internal pudic artery, crossing the spine of the ischium, and entering the perineum. 
10. Inferior hemorrhoidal branches. 11. The superficial perineal artery, giving 
off a small branch, transverse perineal, upon the transversus perinei muscle. 12, 
The same artery on the left side cut off. IS. The artery of the bulb. 14:. The two 
terminal branches of the internal pudic artery; one is seen entering the divided ex- 
tremity of the crus penis, the artery of the corpus cavernosum ; the other, the dor- 
salis penis, ascends upon the dorsum of the organ. 

and the lower part of the sacrum. It is of a triangular form; 
and its attachments are aponeurotic. Its inner and upper 
surface corresponds to the rectum. Its action is to keep the 
coccyx in its proper place, and to assist in forming the iloor 
of the pelvis. 

The isciiio-PECTAL FOSSA is wedge-shapcd, and is from an 
inch and a half to two inches deep. The thin edge looks up- 
wards and corresponds to the splitting of the pelvic fase'ia 
into the levator or anal fascia on the inner side, and the 
obturator fascia on the outer side. The base or thich edge looks 



460 , OF THE PELVIS. 

downwards, and corresponds to t"he integument. The inner 
boundary is formed below by tbe sphincter ani and above 
by the levator fascia, wbicli covers the levator ani muscle; 
while the outer boundary is formed below by the gluteus 
maximus, and above by the obturator fascia, which covers 
the obturator internus muscle. The anterior boundary is 
formed by a reflection of the superficial perineal fascia up- 
wards to join the deep perineal fascia; as the superficial 
perineal fascia is reflected upwards it is joined to the ante- 
rior border of both the obturator and the levator fascia. 
Thus it will be seen that the ischio-rectal fossa is bounded 
on three sides by fascia, especially the upper part of it. The 
jiosterior boundary corresponds to the gluteus maximus and 
coccygeus muscles, and to the sacro-sciatic ligaments and 
foramina. 

A¥hen the contents of the ischio-rectal fossa have been 
removed and its boundaries carefully observed, the student 
should endeavor to obtain a distinct idea of its relations to 
the cavity of the abdomen. He should do this before he 
has attempted to master the anatomy of that portion of the 
perineum which belongs to the genito-urinary apparatus. 
As the ischio-rectal fossa is now fairly exposed, a part of the 
levator fascia should be carefully removed from the levator 
muscle. Having done this, a portion of the muscle should 
also be dissected away when another fascia, the "pelvic^ will be 
observed. Eemove a portion of this and the sub-peritoneal 
areolar tissue together with the peritoneum itself will be seen. 
Thus a clear idea of what separates the abdominal cavity from 
the ischio-rectal fossa will be obtained. It will be seen that, 
besides the peritoneum and the sub-peritoneal areolar tissue, 
the bowels are separated from the ischio-rectal fossa simply 
by the levator ani mnscle and the fasciae that cover its pelvic 
and perineal surfaces. 

It will now also be observed that the pelvic fascia, Fig. 
199 (s), as it descends from the brim of the pelvis, divides 
into three layers. These are the obturator (i 3), the levator or 
anal{\ 5), and the recto-vesical{ s, 1 1). The y^rs^ descends on the 
obturator internus muscle, and is attached below to the ramus 
and tuberosity of the ischium, and to the great sacro-sciatio 
ligament; the second passes downwards on the perineal sur- 
face of the levator muscle to the upper border of the sphinc- 
ter ani, where it is frequently so thin that it hardly deserves 



DISSECTION" OF THE PERINEUM. 



461 



to be regarded as a distinct fascia ; tlie third one, after cover- 
ing the pelvic surface of tlie levator, is reflected to the side 
of the rectum, to the bladder, and the prostate gland. The 
last-named fascia will be more particularly noticed at another 
stage of the dissection. 

That part of the perineum just dissected belongs essentially 
to the lower portion of the intestinal canal ; while the part 
that remains to be dissected belongs more particularly to the 
genito-urinary apparatus. It must be admitted that the latter 
is more complex and difficult to be examined than the former ; 
and it should be remarked here that, although different fasciae 
are spoken of, and have distinct names, they are all con- 
tinuous with each other, and might be regarded as consti- 
tuting a single fascia or aponeurosis. 

By the different reflections and attachments of the fascise, 
there are formed four principal cavities or pockets. Two of 

Fig. 195. 




The Pehinettm, after the Sktn and a Portion op the Superficial PerixeaI- 
Fascia have been rejiovkd. — n, a. Superficial perineal fascia, h. Aoceleratores 
urimo. c, c. Erectores; penis. d,d. Transvorsi perinei. «'. Upper point of sphinc- 
ter ani. /,/. The edges of the glutei mnxiuii. 1, 1. Superficial perineal arteries. 
2, 2. Superficial perineal nerves. 

39^ 



462 OF THE PELVIS. 

these have already been observed ; they contain the levatores 
ani muscles. The other two, which are situated, one above 
and the other below the deep perineal fascia, are now to be 
examined. The latter or lower one contains, besides some 
fat and areolar tissue, the superficial perineal vessels and 
nerves, the erectores penis, acceleratores urinse, and trans- 
versi perinei muscles, and the bulb of the corpus spongio- 
sum ; the former or superior one contains the membranous 
portion of the urethra, including the muscles of Wilson and 
Guthrie, the prostate gland, the neck of the bladder, and the 
vesicul^ seminales. 

The lower one is formed by the deep perineal fascia 
sending off a layer just behind the bulb of the urethra, 
which passes backwards to the rectum and ischio-rectal 
foss^, and then downwards, forming on each side the 
anterior boundary of the ischio-rectal fossa by uniting with 
the levator and obturator fasci3e ; it is then reflected forwards 
beneath the transversi perinei muscles and before the ante- 
rior portion of the sphincter ani muscle, to be lost in the 
scrotum and in the superficial fascia on each side of it. The 
part which is reflected forwards is the superficial perineal 
fascia ; it is attached, laterally, to the tuberosities and rami 
of the ischia, and to the rami of the pubes. 

To dissect this space. Fig. 196, two incisions should be made, 
commencing at a point about two inches and a half in front of 
the anus and extending them backwards, one to the tuberosity 
of each ischium or near to the anterior boundary of the ischio- 
rectal fossa. The fascia included between these two incisions 
is to be raised and reflected backwards as far as the anus and 
the ischio-rectal fossae, but not detached until its connection 
with the deep perineal fascia has been examined ; this cannot 
be done until the contents of the space inclosed by it and the 
deep fascia have been dissected. The remaining portions of 
the fascia are to be reflected laterally, and their attachments 
to the rami of the ischia and pubes observed. The super- 
ficial and transverse perineal vessels and nerves should now 
be examined. 

The superficial perineal artery^ Fig. 194 (i i), enters this space 
just below the transversus perinei muscle, and passes for- 
wards along the inner border of the erector penis muscle. It 
is distributed to the perineum and scrotum. 

The transverse perineal artery^ Fig. 194 (i i), arises sometimes 



DISSECTION OF THE PEKIKEUM. 



463 



from the internal pudic, and sometimes from the preceding 
artery. It accompanies the transversus perinei muscle to the 



Fig. 196. 




The Structures contained between the two Layers of the Deep Perineal 
Fascia, — 1. The symphysis pubis. 2, 2. The rami of the pubes and ischia. 3, 3. 
The tuberosities of the ischia. 4. A triangular portion of the superficial fascia 
turned down, and shown to be continuous with the deep fascia (6, 6, 6). 5, 5. Two 
portions of the superficial perineal fascia reflected laterally, showing its connec- 
tion to the rami of the pubes and ischia. 6, 6, 6. The posterior layer of the deep 
perineal fascia, the anterior layer having been removed. 7. The membranous por- 
tion of the urethra cut across. 8. The superior fasciculus of the compressor urethree 
muscle of one side. 9. The inferior layer o^he compressor urethraa. The two 
fasciculi (8) and (9) constitute Guthrie's muscle of one side. 10. The pubic por- 
tions of the compressores urethrae, or Wilson's muscles. 11. Cowper's glands, partly 
embraced by the inferior layer of the compressor urethra3 muscle. 12. The internal 
pudic artery passing anteriorly to the origin of the compressor urethra). 13. The 
artery of the bulb. 14. The artery of the corpus cavernosum. 15. The arteria 
dorsalis penis. 

perineal centre, supplying ■*:he integument and muscles in 
front of the aaus. The direction of this artery should be 
particularly observed. 

The nerves have the same course and distribution as the 
arteries, which they for the most part accompany. 

After removing the vessels and nerves just examined, and 
also the adipose substance and areolar tissue, of which a con- 
siderable quantity is usuall}^ found in this space, the follow- 
ing muscles will be exposed and should be carefully studied. 
A thin aponeurotic fascia, wliich must not be confounded 

be found investing 



with the superficial perineal fascia, will 



464 OF THE PELYIS. 

and forming for each of them a sheath ; it is connected pos- 
teriorly with the deep perineal fascia. 

The Erector Penis, Fig. 193 (e), occupies the enter por- 
tion of the space. It arises^ tendinous and fleshy, from the 
tuberosity and ramus of the ischium and the ramus of the 
pubes, passes upwards and forwards, and is inserted into the 
corresponding crus of the penis. It draws the crus down- 
wards and backwards, and probably facilitates the erection 
of the penis. 

The Accelerator IIrust^, Fig. 193 (s), is situated to the 
inner side of the preceding muscle. It arises from the peri- 
neal centre, and from the raphe which extends forwards in 
the median line from the centre. Its posterior fibres pass 
upwards and forwards, embracing the bulb, and are inserted 
into the deep perineal fascia ; the middle are inserted into a 
thin tendon above the urethra which is common to" the ac- 
celeratores muscles ; and the anterior fibres terminate in a ten- 
dinous expansion on the side and dorsum of the penis. Its 
action is to compress the urethra. 

The Transversus Perikei, Fig. 193 (?), is a small muscle 
which arises from the inner side of the tuberosity of the 
ischium, near the commencement of the origin of the erector 
penis, and is inserted into the perineal centre. It is frequently 
absent. Its action is to ^ssist m keeping the centre of the 
perineum fixed ; and it may, from the direction of its fibres, 
tend to draw it slightly upwards and backwards. A fasci- 
culus of fibres is sometimes met with here which has been 
denominated the transversus perinei alter. When present, 
this small muscle is usually situated deeper than the trans- 
versus perinei, being covered in by a thin layer of the 
deep perineal fascia. It arises from the rami of the ischium 
and pubes, and is inserted into the side of the bulb. It is not 
unusual to find irregular fasciculi of fibres in this space ; 
sometimes apparently belonging to the transversus perinei, 
and again to the accelerator urinse, or levator ani. 

These muscles may now be raised, but not detached so 
that they cannot be replaced and viewed with reference to 
cutting down upon the membranous portion of the urethra. 
The bulb of the corpus spongiosum should be carefully 
separated from the perineal centre without destroying the 
deep perineal fascia at this point. A triangular space will 



DISSECTION OF THE PERINEUM, 



465 



be observed on eacb side of tbe bulb, at the bottom of which 
tbe 'triangular ligament or deep perineal fascia will be dis- 
tinctly seen ; by seizing hold of that portion of the super- 
ficial perineal fascia which was reflected backwards, and 
making it tense, its connection with the deep fascia will be 
made clear. The tendency of urine when it has escaped from 
the urethra into this space, to pass forwards into the scrotum 
instead of passing backwards into the ischio-rectal fossae, will 
now appear evident. 

The artery of the bulb. Fig. 194 (i 3), should now be sought. 
It arises from the internal pudic between the two layers of the 

Fig. 197. 




A DEEPER Dissection than that represented in Fig. 105, the Perineal 
Muscles being removed and also the Fat in the Isciho-Rectal Foss,e. — a, a. 
Superficial perineal fascia, h. Acceleratores uriiiic. c, c. Crura penis, d. The 
bulb. e. Deep perineal fascia. /, /. Levatores ani, and inferior hemorrhoidal arte- 
ries and nerves, g. Sphincter ani. h,h. Tuberosities of ischia. ^^ A-. Glutei niax- 
iiui. *. Cowper's gland of the left side, and the artery of the bulb just in front 
of it. 1. Internal pudic artery. 2, 2. Superficial perineal arteries and nerves. 

deep fascia at a point nearly opposite to the bulb. It is rea- 
dily found by cautiously dividing the layer tliat covers it at 
the inner side of the corresponding cms penis and reilccting 



4:6Q OF THE PELVIS. 

it to the bulb. The internal pudic itself may be exposed at 
the same time in this part of its course ; it is partly con- 
cealed by the cms, and the ramus of the ischium. The 
artery of the bulb is distributed to the corpus spongiosum, 
being directed, after entering it from behind forwards. 
It will now be seen that this artery, together with the 
transverse perineal and the inferior hemorrhoidal, has a 
transverse direction. The transverse perineal is necessarily 
divided in the lateral operation for stone in the bladder, 
while the artery of the bulb is avoided by not cutting too 
far forwards, and the hemorrhoidal by not extending the 
incision too far backwards in the ischio-rectal fossa. The 
superficial perineal artery may or may not be cut in this 
operation. The position of the internal pudic may be noticed 
at this time with reference to the same operation. It will be 
observed that it lies on the outside of both the ischio-rectal 
fossa and the triangular space between the bulb and the crus 
penis, so that, occupying its normal position, it should never 
be cut in entering the bladder through the perineum. 

The arteries of this region are subject to variations as they 
are in every other part of the body. Instead of one there 
may be two arteries of the bulb ; or this artery may be a 
branch of some other than the internal pudic. There may 
be several hemorrhoidal branches, when the one situated 
anteriorly would almost necessarily be cut in the lateral 
operation for stone. 

The GrLAXDS OF CowPEE, Fig. 197 (*), should now be ex- 
amined. There are two of them. They are situated, each 
one just behind and a little below the bulb, being inclined 
a little to the side of it. Each is about the size of a pea, 
although they vary much in this respect. They have no 
proper capsules, but are placed between the two layers of the 
deep perineal fascia. They will be found by extending the 
dissection that was made for exposing the artery of the bulb 
a little deeper and further backwards. They are usually 
covered below by some fibres belonging to the muscles of 
Guthrie. Their excretory ducts open into the urethra, as 
was mentioned in the description of that organ. The student 
should not be discouraged if he does not find them in his 
first dissection of these parts. A third gland, situated below 
the arch of the pubes, and close to Cowper's glands, has been 



DISSECTION OF THE PERINEUM. 467 

described, and called tlie gland of Litre^ and named by Litre 
the anti-prostatic gland. 

Before proceeding to dissect tlie upper cavity or pocket, it 
will be well to examine tbe deep perineal fascia, immediately 
below the arch of the pubes, and also the levator ani muscle. 
The first may be done by dividing the corpus spongiosum 
and the urethra about an inch anterior to the bulb, and 
dissecting them up as far back as the point where the urethra 
perforates the fascia. A catheter or bougie should be intro- 
duced into the urethra where it has been divided, and carried 
into the bladder. When this is done, the deep perineal fascia 
will be seen attached above to the symphysis pubis, laterally 
to the rami of the pubes ; and below, it will be seen perfo- 
rated by the membranous portion of the urethra. From its 
shape and structure it has been called the triangular liga- 
ment. It consists of two layers, separated by the sub-pubic 
ligament. Only one of these can now be seen. By means 
of this dense fibrous membrane the urethra, which perforates 
it about three-fourths of an inch below the symphysis pubis, 
is at this point firmly fixed in its position. This fact should 
be carefully observed with reference to the introduction of 
instruments through the urethra into the bladder. 

Before examining the levator ani muscle, the continuity of 
the deep perineal fascia with the superficial perineal, the ob- 
turator, and the levator fascioe should be attentively studied ; 
also its connection with the perineal centre. Thus far in the 
dissection no part of these fascise has been cut away or de- 
stroyed so as to prevent a review of them being made, 
which is essential to a thorough understanding of them. To 
examine the levator ani muscle, the lower part of the rectum 
should be slightly drawn down and pushed to one side, while 
some portions of the fasciae just alluded to, including the 
whole of the levator, must be removed. 

The Levator Ani, Fig. 193 (9), is a thin, broad muscle, 
placed on the side of the lower part of the rectum. Its 
origin^ commencing at the symphysis pubis, extends back- 
wards across the obturator foramen to the spine of the 
ischium. Anteriorly, it arises from the symphysis pubis and 
from the body of the pubes; posteriorly, from the body and 
spine of the ischium; the part of the muscle which corre- 
sponds to the foramen, arises from the pelvic fascia, where it 



468 OF THE PELVIS. 

splits to form tlie levator and recto-vesical fascise; a white 
line may be seen from tlie inside of the pelvis corresponding 
to this line of separation. As the fibres descend, the entire 
muscle is inclined obliquely inwards, towards the median 
line of the perineum. The insertion of its fibres extends from 
the coccyx behind, to the perineal centre in front. Those in 
the middle part are inserted into the external sphincter 
and lower part of the rectum ; the posterior fibres into the 
coccyx and a raphe extending from the coccyx to the anus; 
and the anterior fibres into the perineal centre and the rec- 
tum behind the bulb of the urethra. From the origin and 
insertion of this muscle, it will be seen that its pelvic surface 
corresponds to the prostate gland, the neck and lower fundus 
of the bladder, the vesiculee seminales, and the lower part of 
the rectum ; and that, when both of the muscles act together, 
they tend to elevate, and at the same time compress, these 
organs; and, hence, they co-operate with the abdominal 
muscles in the evacuation of the fasces, the urine, and the 
contents of the seminal vesicles. 

The upper cavity or pocket is formed by a reflection of the 
two layers of the deep perineal fascia upwards to join the 
pelvic fascia on the prostate gland and vesicul^ seminales. 
The muscles of Wilson and Guthrie, or the compressores 
urethrse, are placed between these two layers so as to inclose 
the membranous portion of the urethra. These two layers 
of fascia will be better understood when the muscles just 
mentioned have been described. 

The co:mpressoees, or levatores urethra. Fig. 196 
(s, 9, 1 o), are composed of two sets of fibres. Those which 
compose the muscle of Guthrie arise on each side by a short 
tendon from the ramus of the ischium near where it joins 
the ramus of the pubes, and, passing transversely inwards, 
divide into two layers, each of which is inserted into a raphe, 
the one above and the other below the membranous portion 
of the urethra, extending from the bulb to the prostate gland. 
Those described by Wilson form on each side a small fas- 
ciculus, which arises by a narrow tendon from the back part 
of the symphysis pubis about midway between the anterior 
ligaments of the bladder and the pubic arch, and, passing 
downwards, is inserted into the muscle of Guthrie. Both of 
these muscles are fan-shaped, being broader at their insertion 



DISSECTION OF THE PERINEUM. 469 

than at their origin. Their fibres are so intermixed with 
spongy tissue, adipose substance, and bloodvessels, that it is 
often difficult to obtain a clear and satisfactory view of them ; 
and the difficulty is not unfrequently augmented by the blood 
that escapes from the vessels which are divided; they are 
also very feebly developed in some subjects; so that if the 
student does not succeed, in his first attempt to expose these 
muscles, in getting so distinct a view of them as he might 
expect from the description given of them in books, he should 
not be discouraged. In the whole body there is, perhaps, no 
other region in the dissection of which so much depends for 
success upon the character of the subject, as the perineum. If 
the subject be very fat, or the veins distended with blood, or 
the muscles pale and feebly developed, it is almost impossible 
for any one to make a satisfactory dissection or demonstra- 
tion of the parts found in this region. As the membranous 
portion of the urethra is placed between the two layers of 
the muscle of Guthrie, it will be compressed when that muscle 
contracts ; it may also be drawn downwards, which, however, 
is counteracted by the action of the muscle of Wilson, which 
tends to draw it upwards. The- action of the latter seems to 
be in part to steady the former. The glands of Cowper are 
compressed by the lower fibres of the muscles of Guthrie. 
A thin layer of fascia will be found separating the posterior 
fibres of the muscle of Guthrie from the anterior fibres of the 
levator ani. This intermediate fascia is best observed by 
carefully removing the anterior fasciculi of the levator before 
the muscle of Guthrie has been disturbed. Like all other 
intermuscular septa or sheaths of muscles, it varies very 
much in thickness in different subjects. 

Besides the compressores urethrae muscles there will be 
found surrounding the membranous portion of the urethra 
an erectile, elastic fibrous tissue, also several veins or a plexus 
of veins. The dorsal veins of the penis, after perforating the 
sub-pubic ligament and deep perineal fascia, pass through 
this region close to the arch of the pubcs. Fig. 198 (14), to 
reach the vesico-prostatic plexus of veins. 

Before proceediug further with the dissection upwards, 
the upper surface of the pelvic fascia must be exposed by the 
removal of the peritoneum and the subperitoneal areolar 
tissue ; which can be done by partly tearing and partly dis- 
secting them off'. That portion of the pelvic tascia which 
40 



470 



OF THE PELVIS. 



corresponds to tlie ischio-rectal fossa was noticed in tlie 
examination of tliat fossa. It was tlien seen how the levator 
and obturator fascise joined the pelvic; it now remains to be 




A Side View of the Viscera of the Pelvis, showing the Distribution of 
THE Perineal and Pelvic Fascia. — 1. The symphysis pubis. 2. The bladder. 
3, 3. The recto-vesical fold of peritoneum, passing from the anterior surface of the 
rectum to the posterior part of tho bladder; from the upper part of the fundus of 
the bladder it is reflected upon the abdominal parietes. 4. The ureter. 5. The 
vas deferens crossing the direction of the ureter. 6. The vesicula seminalis of the 
right side. 7, 7. The prostate gland. 8, 8. The section of a ring of elastic tissue 
encircling the prostatic portion of the urethra at its commencement. 9. The pros- 
tatic portion of the urethra. 10. The membranous portion, inclosed by the com- 
pressor urethrse muscle. 11. The commencement of the corpus spongiosum penis, 
the bulb. 12. The anterior ligaments of the bladder. 13. The edge of the pelvic 
fascia at the point where it is reflected upon the rectum. 14. An interval between 
the pelvic fascia and deep perineal fascia, occupied by a plexus of veins. 15. The 
deep perineal fascia j its two layers. 16. Cowper's gland of the right side. 17. 
The superficial perineal fascia, ascending in front of the root of the penis to become 
continuous with the dartos of the scrotum (18). 19. The layer of the deep fascia 
which is prolonged to the rectum. 20. The lower part of the levator ani; its fibres 
are concealed by the anal fascia. 21. The inferior segment of the funnel-shaped 
process given off from the posterior layer of the deep perineal fascia, which is 
continuous with the recto-vesical fascia of Tyrrell. The attachment of this fascia 
to the recto-vesical fold of peritoneum is seen at 11. 

noticed, in the first place, how the two layers of the deep 
perineal fascia, which are placed, as has been seen, the one 
above and the other below the muscles of Guthrie, in- 
cluding also the membranous portion of the urethra, join 
the pelvic fascia. This junction takes place around the neck 
of the bladder, and usually on the sides of the prostate gland 
just below the neck. If we examine the layer placed above 
the muscles, we shall find that it joins the pelvic fascia 



DISSECTION OF THE PERINEUM. 



471 



through the medium of the anterior ligaments of the bladder, 
which may be regarded as portions of the pelvic fascia. 
The layer which is placed below the same muscles, after 
covering their under surface, is reflected to the sides of the 
prostate gland and the neck of the bladder, where it joins 
the pelvic fascia just behind the anterior ligaments of the 
bladder; so that we find three fasciae or layers of fascia, 
uniting on the sides of the prostate and the fore part of the 
neck of the bladder, forming a conjoined fascia of the pelvic 
and deep perineal fasciae. The lower layer of the deep pe- 
rineal fascia is not only reflected over the sides of the pros- 
tate, but passes upwards over its lower surface, and also 
over the vesiculse seminales so as to inclose them. 



Fig. 199. 




A Transverse Vertical Section op the Pelvis, showing the distribution 
OF THE Pelvic Fascia. — 1. The bladder. 2. The vesieula seminalis of one side, 
divided across. 3. The rectum. 4. The iliac fascia, covering in the iliacus and 
psoas muscles (5), and forming a sheath for the external iliac vessels (6). 7. The 
anterior crural nerve, excluded from the sheath. 8. The pelvic fascia. 9. Its as- 
cending layer, forming the lateral ligament of the bladder of one side, and a sheath 
to the vesical plexus of veins, 10. The recto-vesical fascia of Tyrrell, formed 
by the middle layer. 11. The inferior layer surrounding the rectum and meeting at 
the middle line with the fascia of the opposite side. 12. The levator ani muscle. 
13. The obturator internus muscle, covered in by the obturator fascia, which also 
forms a sheath for the internal pudio vessels and nerve (14). 15. The layer of 
fascia which invests the under surface of the levator ani muscle, the anal fascia. 

The junction of the deep perineal and pelvic fascia3 
around the prostate gland and neck of the bladder is very 
important when viewed with reference to cutting into the 
bladder through the perineum. It is by means of this cou- 



472 OF THE PELVIS. 

nection tliat the cavity of tlie abdomen is protected against 
effusions of urine in cutting for stone. The pelvic fascia, 
where it is reflected from the parietes of the pelvis to join 
the deep perineal on the sides of the prostate gland and neck 
of the bladder, forms, together with this fascia, a complete 
septum between the abdominal cavity and the space in which 
the incision is made in cutting for stone. The pelvic fascia 
may join the deep perineal so low down as to leave hardly 
space sufS.cient for making the necessary incision without 
wounding the fascia where it is covered by peritoneum. "We 
have seen one instance in which it appeared to us that it 
would be almost impossible to avoid wounding the perito- 
neum in making an incision sufficiently large to remove an 
ordinary sized calculus. The higher up the junction be- 
tween the pelvic and deep perineal fascise takes place, the 
less danger there will be of injury being done to the perito- 
neum. What are sometimes called the lateral ligaments of 
the bladder are those portions of the pelvic fascia which 
are reflected from the walls of the pelvis to the sides of 
the neck of the bladder. They are placed just behind the 
anterior ligaments. All the fascia, or the different layers of 
fascise belonging to the genito-urinary apparatu.s, and several 
connected with the lower part of the alimentary canal having 
now been examined, it will be observed that these fascise are 
not only continuous with each other, but they can be traced 
from the pelvic fascia commencing above just as well as from 
the triangular ligament or deep perineal fascia commencing 
below ; and this should be done by the student. 

Commencing with the pelvic fascia and tracing it down- 
wards from its origin at the brim of the pelvis, the student, 
after having dissected the perineum and studied the pelvic 
viscera, will have little or no difficulty in understanding its 
connections with other fascise, and its relations to the pelvic 
organs. Anteriorly he will observe the manner in which it 
is reflected to the neck of the bladder, and to the sides of the 
prostate gland, forming the anterior and lateral ligaments of 
the bladder, and also a sheath for the anterior portion of the 
vesical plexus of veins; also the manner in which it is con- 
tinuous downwards and forwards with the layers of the deep 
perineal fascia, as they are placed, one above and the other 
below the muscles of Wilson and Guthrie. When the at- 
tachments of the deep perineal fascia to the arch of the 



DISSECTION OF THE PERINEUM. 473 

piibes and tTie rami of the iscbia, and of the pelvic fascia to the 
brim of the pelvis, and then the manner in which these fascisB 
are joined to each other and are connected with the neck of 
the bladder, the prostate gland, and the membranous portion 
of the urethra, are observed, it would seem to be impossible 
for any displacement of these organs to occur. In tracing 
the middle portion of the pelvic fascia, it will be observed 
that it is reflected between the rectum and bladder to join the 
fascia of the opposite side, thus forming what is called the 
recto-vesical fascia^ Fig. 199 (lo), and behind this, to the sides 
of the rectum, in the same way as it was anteriorly to the 
neck of the bladder. The recto-vesical fascia has been called 
the fascia of Tyrrell. It is reflected upwards on the bladder 
in front, and on the rectum behind, becoming more and 
more attenuated until it disappears on the parietes of these 
organs. As it is reflected on the bladder it splits to form a 
sheath for the posterior part of the vesical plexus of veins. 
Fig. 199 (9). Below, it is joined by the deep perineal fascia 
which is continued up behind the prostate gland and the 
vesiculae semiaales, splitting to form a sheath for the last 
named bodies, Fig. 199(2). Where the pelvic fascia is re- 
flected to the rectum, a layer proceeds downwards as far as 
the insertion of the levator ani muscle, separating this mus- 
cle from the rectum ; this is continuous anteriorly with the 
deep perineal fascia behind the prostate gland and vesiculce 
seminales. 

As the anterior part of the pelvic fascia is continuous 
with two layers which belong to the perineum, so is the 
middle portion of it; these are the levator and obturator 
fascia3. The levator fascia is given off from the obturator 
rather than from the pelvic fascia; the continuity, however, 
remains the same. A line having an autero-posterior direc- 
tion is observed at or just above the origin of the levator 
fascia ; it is caused by a thickening of the fascia, and gives 
strength to the upper attachment of the middle portion of 
the levator ani muscle. When it is remembered that the 
levator and obturator fascirc are connected to the layer which 
joins the deep with the superficial perineal lixscia in front of 
the ischio-rectal fossa, the connection of the two last-named 
fascias with the middle portion of the pelvic fascia will bo 
readily seen. 

The posterior part of the pelvic fascia passes behind the 

40'^ 



474 FEMALE ORGANS OF GENERATION". 

rectum, dividing into two layers ; one for the rectum, which 
is continnous anteriorly with the layers given off from the 
middle part of the pelvic fascia ; the other passes between 
the sacral plexus of nerves and the branches of the internal 
iliac vessels, which appear to be furnished with sheaths from 
this fascia ; it is finally lost in dense areolar tissue on the an- 
terior surface of the sacrum. Between the coccygeus and 
the levator ani muscles the levator fascia is joined to the 
pelvic by a thin lamina, thus completing the cavity which 
contains the levator ani muscle. 

From the arrangement of the fascias or aponeuroses in the 
perineum and pelvis, the term, perineo-pelvic fascia might with 
propriety be applied to them generally. It may be observed 
that the fascia which arises from the anterior and lateral 
portions of the brim of the pelvis is continuous all around 
with those which have their origin from the borders of the 
lower strait of the pelvis, and that in passing from one 
border to the other they inclose certain organs so as to keep 
them in situ, or they send off processes which are attached 
to the organs contained in the central part of the pelvis. 



Sect. IY. — Dissection of the Female Organs of 
Generation. 

The genital organs in the female differ so essentially 
from the corresponding ones in the male, that a separate 
examination of them is necessary. It is of the utmost im- 
portance that the student, before he commences this dissection, 
should make himself familiar with the appearance of all the 
parts within the reach of inspection. The vagina should be 
carefully cleansed by means of a syringe, and afterwards the 
finger should be introduced into it, for the purpose of touch- 
ing the OS tineas in situ, of ascertaining its distance from the 
exernal orifice of the vagina, and how far the finger must be 
introduced in order to reach it, so as to be able to judge fairly 
of its condition. This should be practised after the cavity 
of the abdomen has been opened, so that the relations of the 
vagina to that cavity may be observed. The relation that 
exists between the vagina and the peritoneum is exceedingly 
important; every student should observe this for himself. 
The introduction of the speculum into the vagina, and of a 



FEMALE ORGANS OF GENERATION. 475 

probe or bougie into the os uteri, may be practised in the 
dissecting-room to considerable advantage. It is, perhaps, 
equally important to become familiar with the parts involved 
in carrying an instrument through the urethra into the blad- 
der. The student should observe for himself what points he 
could rely on to guide him in conducting the catheter to the 
meatus urinarius, and thence into the bladder. It has happened 
that through the neglect of acquiring the necessary familiarity 
with the exact position of the external orifice of the urethra, 
and its relations to the surrounding parts, the young phy- 
sician has been subjected to feelings of chagrin and mortifi- 
cation, in consequence of his having failed to introduce the 
catheter the first time he attempted it in his practice; or 
if he has not failed, he has been compelled to make an im- 
proper exposure of the person of his patient in order to 
succeed. One or two hours devoted to the examination of 
these parts, and to the practice of introd^icing the catheter, 
in the dissecting-room, will be worth more than all that can 
be learned from reading-books on this subject. 

The female organs of generation are divided into the 
external and internal. In the latter are included the uterus^ 
the ovaries^ and the FaJh'pian tubes ; in the former, the vagina 
and the parts that constitute the vulva, which are the mons 
veneris^ the lahia majora and minora^ the anterior and posterior 
commissures^ the fourchette^ the fossa navicularis^ the clitoris^ 
the vestibule^ the meatus urinarius^ the hymen^ and the carun- 
culce myrtiformes. All these parts should be carefully in- 
spected in situ. 

The Mons Yeneris, Fig. 200 (3), is an eminence placed 
in front of the symphysis pubis and the pubic bones. It is 
formed by areolar tissue and adipose substance, situated be- 
neath the integument, which in adult life is covered with hair. 

TheLABL^. Majora, Fig. 200 (1, 1), are situated below the 
mons veneris, one on each side of the rima^ or the fissure 
that leads to the vagina. Each consists of a fold of the 
integument, which contains a substance resembling the dar- 
tos in the male, areolar tissue and fat, besides vessels, nerves 
and sebaceous follicles. Its free border is round, and thicker 
than its attached border; it is also thicker above than be- 
low. Its external surfiice is continuous with the skin and 
covered with hair, while its internal surface is continuous 



476 FEMALE OEGANS OF GENERATION. 

witli the mucous membrane of the vagina, so that the skin 
blends with the mucous membrane on its free border. The 
rima or opening between them has an elliptical form. The 
labia become exceedingly attenuated during parturition, but 
very soon recover their natural form and condition. From 
the quantity of loose areolar tissue which they contain, they 
are very liable to serous infiltration. 

The ANTERIOR and posterior commissures are situated, 
the former at the anterior junction of the labia majores, and 
the latter. Fig. 201 (e), at their posterior junction. They are 
merely the extremities of the rima vulvae. 

The FouRCHETTE or Fr^t.nulum Labiorum, Fig. 200 (2), 
is a small duplicature of the mucous membrane placed a 

Fig. 200. 




A View of the External Organs or Generation in the Virgin — the Vulva 
BEING partially OPEN. — 1, 1. Labia majora. 2. Fourchette. 3. Mons veneris. 
4. Prepuce of the clitoris around the glans clitoridis. 5. Vestibule. 6, 6. The 
nymphse. 7, 8. The hymen, open in its central portion and surrounding the infe- 
rior extremity of the vagina. 9. The perineum. 10. The anus. 

short distance behind the posterior commissure. It is fre- 
quently lacerated and destroyed during the first parturition. 

The Fossa ISTavicularis is a small depression situated 
between the posterior commissure and the fourchette. 

The Labia Minora or Nymphs, Fig. 200 (6,6), are folds 
of the mucous membrane placed within the labia majora. 
If they be traced from below, they will be found to com- 
mence, one on each side, near the middle of the junction 



FEMALE OEGANS OF GENEEATION. 477 

of the labia majora with the vagina and to extend upwards, 
gradually increasing in size and approaching each other. 
About three-fourths of an inch below the anterior com.- 
missure each one bifurcates, or divides into two folds, an 
wpiper and a lower ^ which unite in the median line with 
those of the opposite side. The duplicature formed by the 
junction of the two upper folds constitutes the jpreputium 
clitoridis^ Fig. 200 (4), while that. formed by the two lower 
joins the glans clitoridis, or the anterior and lower part of 
the clitoris; it seems to correspond to the fraenum of the pre- 
puce of the penis. The nymphs vary very much in size in 
different persons ; sometimes they are seen projecting beyond 
the labia majora, and then agaiu they are so small that they 
can hardly be recognized as distinct bodies. They contain 
numerous small sebaceous follicles. 

The Clitoeis, Fig. 203 (7), corresponds to the penis in the 
male. It is placed below and in front of the symphysis 
pubis between the labia majora and above the urethra. It 
resembles somewhat in its formation the penis. It has two 
corpora cavernosa^ which are connected by their crura to the 
rami of the ischia and pubes. It has no corpus spongiosum 
although it has a glans^ which is situated on the anterior ex- 
tremities of the corpora cavernosa; it is composed of erectile 
tissue. 

The corpora cavernosa are formed nearly of the same tis- 
sues as the corresponding bodies in the penis. Each crus 
has a muscle resembling in its origin and insertion the erec- 
tor penis. It is called the erector clitoridis^ Fig. 203 (e). The 
clitoris, also, has a suspensory ligament. The clitoris, like 
the nymphse, varies greatly in size. It is said to have be- 
come very much enlarged under the influence of certain 
habits, such as constant titillation. 

The Yestibule, Fig. 200 (5), is a smooth triangular 
surface, bounded laterally by the nymphae, below by the 
meatus urinarius, and above by the inferior folds of the 
nymphc^. This space should be observed with reference to 
the introduction of the catheter; for when this surtace is 
found, there will usually be but little dilTicult}^ in determin- 
iog the exact position of the orifice of the urethra. 

The MEATUS UEINABIUS, Fig. 205 (7), or external orifice of 



478 FEMALE OEGANS OF GENERATION. 

the urethra is situated in the median line and midway between 
the nymphse and just above the upper projecting edge of the 
vagina. It is surrounded by a slight elevation or ridge 
formed by the mucous membrane, and, beneath this, by a 
band of fibres which cause a slight constriction. It is gene- 
rally closed. 

The HYMEN, Fig. 200 (7,8), consists of a fold of mucous 
membrane placed at the entrance of the vagina. It varies in 
shape, being sometimes crescentic with the concavity looking 
upwards; and, again, consisting of a transverse band with an 
opening above and below it ; or it may form a ring having 
an opening in the centre with a fringed margin. It may en- 
tirely close the external orifice of the vagina so as to prevent 
the escape of the menstrual discharge. It is very rarely met 
with in the dissecting-room. Its absence does not afford any 
certain evidence of the loss of virginity. 

The CARUNCUL^ MYRTiFORMES, Fig. 201 (25, 25), are the 
remains of the hymen. They consist of small reddish bodies 
attached to the sides and the lower part of the opening into 
the vagina. 

Yagina. 

The VAGINA is placed between the vulva and the uterus, 
being from four and a half to five and a half inches in length ; 
as it is curved, with the concavity looking forwards, its pos- 
terior wall is somewhat longer than the anterior. Its anterior 
wall corresponds to the bladder and urethra, while the pos- 
terior wall corresponds to the cavity of the peritoneum, the 
rectum, and the perineum. Its axis corresponds to that of 
the lower part of the pelvis. It is larger above than below ; 
in this respect it is the reverse of the rectum. Its anterior 
and posterior walls are in apposition, although in drawings 
they are represented as separated some distance from each 
other. The cervix of the uterus projects into it at its upper 
extremity, the posterior lip more than the anterior. This 
results from its attachment to the uterus being a little higher 
behind than before. 

It is lined by a vascular mucous membrane. Transverse 
rugoe are observed on its upper and lower surfaces. These 
do not, like the rug^ of mucous membranes generally, disap- 



VAGINA. 



479 



pear when the organ is distended. They are more numerous 
on the superior than the inferior wall, and are more distinct 
in the infant than in the adult. There is a longitudinal ridge 



Fig. 201. 




View of the Uterus, Ovaries, Fallopian Tubes, Kound Ligaments, Va- 
gina AND Vulva — 1. Anterior face of the uterus covered by the peritoneum. 2. 
Its fundus. 3. One of its superior lateral angles near the origin of the Fallopian 
tubes. 4. Side of the uterus. 5. 5. Its neck embraced by the upper end of the 
vagina. 6, 6, 6, 6, 6. The broad ligaments. 7, 7. The ovaries drawn up by hooks 
above their natural position. 8, 8. The ligaments which unite the ovaries to the 
uterus. 9, 9. Fallopian tubes. 10, 10. Enlargement near their extremities. 11,11. 
Their trumpet-shaped mouths. 12, 12. The pavilions. 13, 13, 13, 13. Corpora fim- 
briata. 14, 14. Portions of the fimbriated processes running to the ovaries. 15. 
Section of one of the round ligaments. IG, 16, 16, 16. A longitudinal section of 
the vagina. 17, 17. External surface of the vagina. 18, 18. Its internal anterior 
parietes. 19. Longitudinal lines forming a sort of raphe on its posterior Avail. 
20, 20. Transverse wrinkles or folds. 21. Anterior lip of the os uteri. 22. Its pos- 
terior lip. 23. Os uteri externum. 24. Perineum. 25, 25. Carunculre niyrtiformes 
drawn out. 26. Posterior commissure of the vulva forcibly drawn out. 27. The 
anus. 28. Labium majus everted. 29,29. The two halves of the clitoris and the 
labia minora forcibly separated. The rectum, cut off and tied, is seen behind; the 
bladder and other parts have been removed in front. 

in the median line of both the upper and the lower wall. 
These are named the columns of the vagina, Fig. 201 (19). 
The mucous membrane is covered by a squamous epithelium. 
It contains numerous follicles and papilla^ especiall}^ near its 
external orifice. It is continued into the uterus alDove, and 



480 



FEMALE ORGANS OF GENERATION. 



prolonged downwards to be lost in the skin on tlie labia 
majora. 

Besides the mucous membrane tbe walls of tlie vagina 
contain a layer of erectile tissue inclosed in two quite thick 

Fig. 202. 




Front View of the Erectile Structures of the External Organs op Gene- 
ration IN THE Female. — a. Bulbus vestibuli. h. Sphincter vaginae muscle, e, e. 
Venous plexus. /. Glans of the clitoris, g. Connecting veins, h. Dorsal vein of 
the clitoris, k. Veins going beneath pubes. I. The obturator vein. 

layers of fibrous structure, and outside of these a layer 
similar to the dartos in the scrotum of the male. The erec- 
tile tissue is more abundant near the external orifice than 
above near the uterus. The hulhi vestibuli^ Fig. 202 (a), are 
situated, one on each side, at the lower part of the vagina, 
between it and the nymphse and vestibule. They are sup- 
posed to be analogous to the bulb of the corpus spongiosum 
of the penis. Each is about an inch in length. They are 
covered by the mucous membrane. 

The anterior wall is thicker than the posterior, especially 
in the median line, where the urethra is imbedded in it. 
The peritoneum descends between the rectum and vagina, 
Fig. 205, so as to cover about one-fourth of the posterior wall 
of the latter organ. The parietes of the vagina are very 



VAGINA. 



481 



distensible, as is shown in parturition. A part of the fibres 
of the levatores ani mascles, Fig. 203 (4), are spread out on 
the sides of the vagina. 

The Sphincter Vaginje Muscle, Fig. 203 (2), surrounds 
the vagina close to its external orifice. It is exposed by re- 
moving the integument from the perineum and labia majora. 
Its fibres arise from the centre of the perineum, and, passing 
upwards and forwards on the sides of the vagina, are inserted 
into the corpora cavernosa of the clitoris, some fibres passing 
on to the suspensory ligament. This muscle is narrow at its 
origin and insertion, but spreads out on the parietes of the 
vagina. It corresponds to the ejaculator urinse in the penis. 
Its action is to constrict the anterior orifice of the vagina. It 
also compresses the glands of Bartholine or the vulvo-vaginal 
glands^ two small bodies situated, one on each side, between 

Fig. 203. 




A View op the Muscles op the Peuinefm in the Pemalf. — 1. Tuber ischii. 2. 
Sphincter vagina?. 3,3. Its insertion into tlie clitoris, -t. Vnginiil ring of the same 
muscle, which receives a part of the fibres of the levator ani. 5. Intercrossing of 
the sphincter ani and sphincter vagiiuv nui*cles at the perineal centre. 6. Erector 
clitoridis. 7. The clitoris, covered by its prepuce. 8. Transversus perinei muscle. 
9. Sphincter ani. 10. Levator uni. H. The gracili:*. 12. Adductor magnus. 13. 
Posterior part of the gluteus maxiiuus. 

41 



482 FEMALE OKGANS OF GENEEATION. 

the vagina and tlie erector clitoridis. They open by small 
ducts, about half an inch in length, close to the lateral and 
posterior caruncul^, by which they are usually concealed. 

The vulva is supplied with arteries derived principally 
from the internal and external pudic. The vagina receives 
branches from the internal pudic and uterine. Besides the veins 
that correspond to the arteries, there are several plexuses^ 
belonging both to the vulva and the vagina. Those of the 
vulva communicate with the vaginal, and these again with 
the hemorrhoidal. The vaginal are quite large; they are 
found on both sides of the vagina. The attention of the 
student should be directed especially to the great vascularity 
of these parts, and its influence on the pathological condition 
of them. 

The Urethea, Fig. 205 (e), should be examined in con- 
nection with the anterior wall of the vagina. It is from one 
to one and a half inches in length, and corresponds to the 
membranous portion of the male urethra. Its direction is 
downwards and forwards. It is lined by mucous membrane 
which presents longitudinal folds and mucous crypts. The 
mucous membrane is surrounded by a layer of spongy erec- 
tile tissue, and this again by a muscular layer of circular 
fibres. Some of the longitudinal fibres of the bladder are 
prolonged into the walls of the urethra. It is susceptible of 
considerable dilatation, which greatly facilitates the removal 
of calculi from the bladder. It is in relation, above, with 
the crura of the clitoris, with the anterior ligaments of the 
bladder, and a plexus of veins. It perforates the deep peri- 
neal fascia, and also passes between its layers. The muscles 
of Wilson and Guthrie have the same arrangement as they 
have in the male. 

The perineum should be examined with reference to the 
support it affords to the parts placed above it, and also with 
reference to parturition. It is wedge-shaped ; the thick end 
or base corresponds to the integument, while the thin end is 
lost in the recto-vaginal septum. 

The bladder^ Fig. 205 (4), in the female has the same struc- 
ture as in the male. It differs somewhat in its shape, being 
usually larger and more globular. This, however, may be 
owing to pregnancy, and to the habits of the sex, or the cir- 
cumstances which surround the female. The uvula vesicse 
is not quite so large as in the male, which favors the dis- 



UTEEUS. 483 

cliarge of calculi from the bladder before they have acquired 
too great a size. 

Uterus. 

The uterus, Fig. 204, is placed in the upper and central 
part of the pelvis, between the bladder and the rectum, being 
inclined forwards in those who have not borne children, so 
as to form an angle with the vagina. As seen in the dissect- 
ing room, it has, perhaps, in a large majority of cases, under- 
gone some displacement, being most frequently inclined 
backwards. It does not reach the brim of the pelvis, and is 
frequently observed to be very much below it. A large 
portion of it is invested by peritoneum, which covers the 
fundus, the whole 'of the posterior and the upper three- 
fourths of the anterior surface, the remaining fourth being 
in contact with the bladder. The parts covered by the peri- 
toneum present a free surface, which is constantly in appo- 
sition with another surface covered by peritoneum. The 
lower extremity projects into, and is embraced by, the 
vagina, which is attached to it higher up posteriorly than 
anteriorly. Each border below the fundus has attached to 
it the broad ligament which extends, laterally, to the sacro- 
iliac symphysis, and, with the uterus and the corresponding 
ligament on the opposite side, divides the pelvic cavity trans- 
versely into two culs-de-sac. Between the layers which form 
this fold of peritoneum, are found the round ligament, the 
ovarian ligament, and the Fallopian tube. The relative 
position of each of these parts should be noticed. Where 
they are attached to the uterus the Fallopian tube is placed 
above the other two, and partly between them, while the 
ovarian ligament is situated a little lower than the round 
ligament. 

The round ligament, or ligamentum teres, Fig. 201 (s), passes 
outwards, upwards, and forwards, to the inguinal canal, 
through which it passes to reach the mons veneris and the 
corresponding labium majus, with which it becomes blended. 
It is surrounded by a layer of peritoneum, which forms what 
is called the canal of Nuch. It is composed of a venous 
plexus, of arteries, of a plexus of nerves, and of muscular 
fibres. Its use is said to be to support the uterus, and to 
assist in keeping it in the axis of the pelvic cavity. It is 
very evident, from its size and structure, that it cannot con- 



484 



FEMALE OEGANS OF GENEEATION". 



tribute much, if any, to this purpose. It may place in direct 
sympathetic relation the uterus with the external organs. 

The ovarian ligament Fig. 204 (p), is about two inches in 
length. It is composed of fibro-muscular tissue, and passes 
outwards to be inserted into the ovary. It retains the ovary 
in situ. 

The Fallopian tuhe, Fig. 204 (s), extends laterally towards 
the brim of the pelvis. It is from four to five or six iiiches 

Fig. 204. • 




Posterior View of the Uterus and its Appendages, the Cavity of the 
Uterus beixg shown by the removal of its posterior Wall, and the Vagina 
being laid open. — a. Fundus, h, body, and c, cervix of the uterus laid open. The 
arbor vitae is shown in the cervix; at the constriction just above it is the os uteri 
internum, d. The os uteri externum, e. The interior of the upper part of the 
vagina. /. Section of the walls of the uterus, i. Opening into right Fallopian 
tube, o, o. Ovaries, p, ]). Ligaments of ovaries, r. Broad ligament, s, s. Fallo- 
pian tubes, t, t. Fimbriated extremities. 

long ; placed in the upper border of the broad ligament, it 
forms a curve with the concavity looking downwards and a 
little backwards. Its free extremity is usually observed close 
to the ovary. When this is examined, it will be found to 
present a fimbriated arrangement ; this is best seen when it 
is allowed to float in water. It is also expanded or funnel- 
shaped, which enables it to grasp a part of the ovary, and to 
receive with greater certainty the ovum which is about to 
escape from that body. This end of it has been named the 
corpus fimbriatum, Fig. 204 (^), and also the morsus diaholi. 
The Fallopian tube is composed of a serous or peritoneo2^ a 
micscular and a mucous layer. The mucous membrane is con- 



UTEEUS. 485 

tinuous at the uterine orifice with the lining membrane of the 
uterus, and is blended at its free extremity with the peritoneum. 
It affords the only instance in the body where a mucous and 
serous membrane are continuous, or where a serous cavity 
has an external communication. It is covered with ciliated 
and columnar epithelia ; it also presents longitudinal rugae 
or plic98. The muscular ls,jer is a prolongation of the mus- 
cular tissue of the uterus. It consists of a longitudinal and 
circular set of fibres. The uterine orifice will be seen when 
the cavity of the uterus is exposed. The fimbriae are very 
frequently met with more or less obliterated by adhesions to 
each other, or to the surrounding parts. 

The uterus varies in size, and hence its dimensions vary 
as given by different writers. It is usually from two inches 
and a half to three inches in length, an inch and a half to two 
inches in breadth, and about three-fourths of an inch thick. 
In women who have borne children it is larger than in those 
who never have. It is divided into the fundus, body, and 
cervix. The fundus. Fig. 204 (a), is the part above the attach- 
ments of the Fallopian tubes ; the cervix, Fig. 204 (c), is the 
lower part, being separated from the body. Fig. 204 [b), or 
the portion between the fundus and cervix, by a slight con- 
striction. Its weight varies from one to two ounces, accord- 
ing as it varies in size. 

In form, it resembles a pear flattened on two sides, being 
a little more convex posteriorly than anteriorly. The cervix 
is constricted at both ends, being shaped like a wine-cask. 
The part that projects into the vagina is divided by a trans- 
verse fissure into an anterior and a posterior lip. The latter 
is not quite so thick as the former, but appears, when exa- 
mined in situ, to be a little more prominent, or to project a 
little more than the former, which is owing to the vagina 
being inserted higher on the cervix behind than in front. 
The vaginal orifice has been called the os uteri, os ideri exter- 
num, or OS tiucce. Fig. 204 (il), from a fancied, resemblance it 
has to the mouth of the tench fish. 

It is exceedingly important that the student should obtain 

a correct idea of the cervix of the uterus when in a perfectly 

healthy state, in order that he may be able to detect any 

deviation from a strictly physiological condition. The time 

has been when a student could graduate in a respectable 

institution without fooliuo- that he might be required at a 

4t-x- 



486 



FEMALE 0BGAN3 OF GENEKATION. 



very early period, or perhaps at any period in Ms practice, 
to inspect the cervix of the womb, and determine its condi- 
tion in regard to health or disease. No one, however, can 
do this at the present time without proving false to himself 
and to those who shall confide in his professional skill. 
Drawings prepared by the most skilful artists may be within 
his reach, but they alone should not satisfy his desire 
for accurate knowledge. They may be invaluable as aids, 
but should never be relied on exclusively as substitutes for 
nature. Is there not just reason to apprehend that the vis- 



Fig. 205. 




A Vertical Section of the Female Pelvis and Viscera. — 1. The symphysis 
pubis, to the upper part of which the tendon of the rectus muscle is attached. 2. The 
abdominal parietes. 3. The collection of fat, forming the projection of the mons 
veneris. 4. The urinary bladder. 6. The entrance of the left ureter. 6. The 
canal of the urethra, converted into a mere fissure by the contraction of its walls. 
7. The meatus urinarius. 8. The clitoris, with its prfeputium, divided through the 
middle. 9. The left nympha. 10. The left labium majus. 11. The meatus of the 
vagina, narrowed by the contraction of its sphincter. 12. The canal of the vagina, 
upon which the transverse rugae nre apparent. 13. The thick wall of separation 
between the base of the bladder and the vagina. 14. The wall of separation be- 
tween the vagina and rectum. 15. The perineum. 16. The os uteri. 17. Cervix 
uteri. 18. The fundus uteri. The cavity of the uterus is seen in the centre of 
the organ. 19. The rectum, showing the disposition of its mucous membrane. 20. 
The anus. 21. The upper part of the rectum, invested by the peritoneum. 22. The 
recto-uterine fold of the peritoneum. 23. The utero-vesical fold. 24. The reflection 
of the peritoneum, from the apex of the bladder, upon the urachus, to the internal 
surface of the abdominal parietes. 25. The last lumbar vertebra. 26. The sacrum. 
27. The coccyx. 



UTERUS. 487 

cera contained in the pelvis receive altogether too small a 
share of the attention of the student in the dissecting-room, 
the only place where a proper knowledge of them can be 
acquired ? 

The cavity of the uterus may be exposed by simply mak- 
ing a vertical incision through its parietes, and forcibly 
separating the cut edges, or it may be done by making a 
transverse vertical incision, so as to divide it into two equal 
parts, one being the anterior and the other the posterior half. 
The walls of the uterine cavity vary in thickness at different 
points. Where the Fallopian tubes join them, they are not 
more than two or three lines thick ; the anterior and posterior 
walls are from four to six lines thick ; the walls of the cervix 
are not so thick as those of the body. Like the vaginal, the 
anterior and posterior surfaces of the uterine cavity are con- 
stantly in apposition. Owing to the great thickness of the 
walls, the cavity is comparatively very small. It has the shape 
of a curvilinear triangle, the superior angles corresponding to 
the mouths of the Fallopian tubes, and the lower angle to the 
05 uteri internum^ or isthmus uteri^ Fig. 204 (c), the opening be- 
tween the body and the cervix, or, if the latter be included, 
the OS externum. The mucous membrane is very thin and 
delicate, so much so that its existence has been denied or 
doubted by some. It is more vascular in the body than in 
the cervix, especially during the menstrual period. In the 
cervix, a vertical ridge or column is observed in the median 
line both on the anterior and posterior wall, from which pro- 
ceed other ridges at an obtuse angle. The term arhor vitce 
uterina^ Fig. 204 (c), has been employed to designate this 
appearance. It commonly becomes less apparent after the 
first parturition, although not necessarily so. ISTumerous fol- 
licles may be noticed in the cervix, especially near its external 
OS, and some in the body. They have been named the ovula 
of Naboth from the circumstance that Naboth happened to 
observe them in a diseased condition, and thinking they were 
ovula, described them as such. 

The openings that lead into the Fallopian tubes, Fig. 204 
(?'), are so small that they are scarcely perceptible to the 
naked eye. The cavity is elongated towards them so as to 
form cornua. 

The muscular coat of the uterus is hard, dense, and of a 
grayish color. It consists of fibres, which, in the uninipreg- 
nated uterus, cannot be traced on account of thoir oonipact- 



488 FEMALE ORGANS OF GENERATION. 

ness and interlacing apparently in every direction. Tliey 
are non-striated, and hence belong to those of organic life. 
They are arranged in the body in a superficial and a deep- 
seated layer. Anteriorly and posteriorly the swperjicial have 
a longitudinal direction; laterally they are oblique, and are 
prolonged into the round and ovarian ligaments, and into the 
walls of the Fallopian tubes. The deep-seated are arranged in 
the form of tAVO hollow cones, the bases of which correspond 
to the median line, interlacing with the fibres of the opposite 
side, while the apices surround the cornua, and extend into 
the Fallopian tubes and the round and ovarian ligaments. 
The cervical portion of the muscular coat consists of circular 
fibres which interlace and cross each other. 



The Ovaries. 

The ovaries^ Fig. 204 (o), are the analogues in the female, 
of the testes in the male, ^here are two of them, one on 
each side. Each is placed between the layers of the broad 
ligament, behind the Fallopian tube, and about two inches 
from the uterus, to which it is connected by the round and 
broad ligaments. It is a small oval body flattened on the 
sides from before backwards. They increase in size during 
pregnancy, and like the testicles, become atrophied in old 
age. Their anterior, posterior, and upper surfaces are free. 
One or more of the fimbrise are usually attached to their 
outer extremities. Immediately under the peritoneum is a 
thick, dense, fibrous coat, corresponding to the tunica albu- 
ginea of the testicle. The peritoneum adheres to this in the 
same manner as the tunica vaginalis testis adheres to the 
testicle. From the inner surface fibrous bands are sent in- 
wards into a cellulo-vascular substance named the stroma. 
Besides the fibrous and serous coats there is a vascular one, 
similar to the tunica vasculosa of the testicle. Throughout 
the stroma are distributed the Graafian vesicles; they vary 
YQYj much in size and number. They can be best observed 
just after parturition, when the ovaries are soft and swollen. 
Each vesicle consists of two coats, an external and internal, 
and contains a yellowish fluid and an ovum. When a vesicle 
ruptures, and the ovum escapes, the remains of the vesicle, it 
it is supposed, forms a brownish-yellow bodj^ called corpus 
luteum. 



THE LOWEE EXTREMITY. 489 

The vessels and nerves of the uterus and ovaries are no- 
ticed in the dissection of the vessels and nerves of the pelvic 
cavity. 



CHAPTER II. 

OF THE LOWER EXTREMITY. 

Sect. I. — Dissection of the Anterior Part of the Thigh. 

The position and connections of the parts concerned in 
femoral or crural hernia are such that the examination of 
them naturally precedes the general dissection of the anterior 
part of the thigh; hence it will be unnecessary to describe 
again the parts which have been examined specially as well 
as in their relations to femoral hernia. 

Anatomy of Femoral Hernia. 

In femoral or crural hernia the bowel protrudes under 
Poupart's ligament, near its insertion into the spine and crest 
of the pubic bone. The parts which are involved in this 
form of hernia are situated below, behind, and above Pou- 
part's ligament. Those below it are the skin, the superficial 
fascia including the vessels, nerves, and lymphatics which are 
found in it, the fascia lata and the infundibuliform sheath of 
the femoral artery and vein ; behind it are found the psoas 
magDUS and iliacus internus muscles, the anterior crural 
nerve, the external iliac artery and vein, the infundibuliform 
sheath, and the femoral ring; above it and in the abdomen 
are the peritoneum, the sub-peritoneal areolar tissue, and the 
fasciae trans versalis and iliaca. 

The parts in the thigh below Poupart's ligament can be 
exposed without opening the cavity of the abdomen; but 
the dissection of the parts placed behind and above it, require 
this cavity to be opened. The integument nnist be dissected 
off' from the anterior portion of the upper third of the thigh. 
This may be done by making an incision through the skin, 
♦from the anterior superior spinous process of the ilium, 
directly downwards to the middle third of the thigh, and 
then extending it transversely across to the inner side of 



490 



THE LOWEE EXTREMITY. 



Fig. 206. the thigh. It is supposed that the 

parts in the inguinal region have al- 
ready been dissected, so that no new 
incisions will be required above Pou- 
part's ligament. 

Having exposed the superficial fas- 
cia, the student should now look for 
the subcutaneous vessels, nerves, and 
lymphatic glands in this region. 

The arteries are the arteria ad cutem 
abdominis, the external circumflex 
ilii, the superficial external pudic, and 
the inguinal branches. They all arise 
a short distance below Pou part's liga- 
ment ; sometimes two or three of them 
arise by a common trunk. 

The arteria ad cutem ahdorainis^ or 
superficial epigastric^ Fig. 206 (2), 
passes upwards and inwards over Pou- 
part's ligament, in the direction of the 
umbilicus. It is distributed to the 
integument. 

The superior external pudic^ Eig. 206 
(le), goes inwards to supply the in- 
tegument on the pubes, the penis, and 
the scrotum. 

The external circumflex ilii, Fig. 206 
(15), passes outwards towards the an- 
terior superior spinous process of the 

A View of the Anteetok and Inner Aspect of the Thigh, showing the 
Course and Branches of the Femoral Artery. — 1. The lower part of the 
aponeurosis of the external oblique muscle ; its inferior margin is Poupart's liga- 
ment. 2. The external abdominal ring. 3, 3. The upper and lower parts of the 
sartorius muscle; its middle portion having been removed. 4. The rectus. 5. The 
vastus internus. 6. The patella. T. The iliacus and psoas ; the latter being 
nearest the artery. 8. The pectin eus. 9. The adductor longus. 10. The tendi- 
nous canal for the femoral artery formed by the adductor magnus and vastus in- 
ternus muscles. 11. The adductor magnus. 12. The gracilis. 13. The tendon 
of the semi-tendinosus. 14. The femoral artery. 15. The external circumflex 
ilii artery taking its course along the line of Poupart's ligament, to the crest of the 
ilium. 2. The superficial epigastric artery. 16. The two external pudic arteries, 
superior and infei'ior. 17. The profunda artery giving off" 18, its external circumflex 
branch: and lower down the three perforantes. A small portion of the internal cir- 
cumflex artery (8) is seen behind the inner margin of the femoral, just below the 
deep external pudic artery. 19. The anastomotica magna, descending to the knee, 
upon which it ramifies (6). 




ANATOMY OF FEMOEAL HERNIA. 



491 



ilium, where it is lost in the integument. Fig. 208. 

The inguinal branches supply the lymph- /V 



Fig. 207. 




Plan of the Cutaneous Nerves on the Front of 
THE Thigh. — 1, 2. Branches of the superior and mid-- 
die musculo-cutaneous nerves. 3,3. Branches of exter- 
nal cutaneous nerve. 4. Branches of middle cutaneous 
nerve. 5, 5. Internal cutaneous ; the lower number re- 
fers to the anterior division of this nerve. 6. Long or 
internal saphenous nerve, when become subcutaneous. 
7. Crural branch of the gcnito-crural nerve. 

atic glands and areolar tissue in this 
region. 

The principal vein is the internal sa- 
phenousj Fig. 208. This is situated on 



^ i'" 



Saphenous Opening in the Fascia Lata, Internal Saphenous Vein, &c — 
1. Saphenous opening, a. External epigastric vein. b. External pudic vein. c. 
Superficial circumflex ilii. d. Beginning of external saphenous vein. 



492 THE LOWER EXTREMITY. 

the inner and anterior part of the thigh, and lies close to 
the fascia lata. It receives several branches, Fig. 207 (a, 6, c), 
some of which accompany the arteries already described. 

The nerves (Fig. 207) are derived from the lumbar plexus, 
the genito-crural, and the anterior crural. They penetrate 
the fascia lata obliquely at different points, and after run- 
ning some distance they leave it to become subcutaneous. 
The integument on the upper and anterior part of the thigh 
is supplied principally by three branches. One of them, a 
branch of the suj^erior musculo-cutaneous^ reaches the thigh 
through the external abdominal ring; another one, a branch 
of the gerdto-crural^ passes through the fascia lata just be- 
low the middle of Poupart's ligament ; the third one, a 
branch of the inferior musculo-cutaneous or the external cuta- 
neous nerve, pierces the fascia below the anterior superior 
spinous process of the ilium. The middle cutaneous nerve 
sometimes becomes subcutaneous near the junction of the up- 
per with the middle third of the thigh, but usually lower 
down. Yery little importance is attached to these nerves in 
connection with the anatomy of femoral hernia. 

The lymjjhatic glands, Fig. 148 (7), are divided into the 
deep and superficial; the former are placed beneath the fascia 
lata, and the latter are imbedded in the superficial fascia. 
The superficial are again divided into the superior and infe- 
rior ; the superior lie along Poupart's ligament, some above 
and others below it ; the inferior are situated near the saphe- 
nous vein. These glands are frequently found enlarged, so 
that the student can often get in his dissection a distinct 
view of their location. They vary in number in different 
subjects; sometimes several are joined together. The super- 
ficial lymphatics of the penis pass through the glands situated 
near Poupart's ligament, and hence the liability of these to 
become affected in venereal disease. 

The superficial fascia should now be removed. It m.ay be 
raised and reflected in the same manner as the skin was ; or 
it may be turned off from above downwards and from within 
outwards. The saphenous vein must be dissected out as far 
up as where it enters the saphenous opening, cutting it 
across below but not above, as its connection with the infun- 
dibuliform sheath of the femoral vessels should be, for the 
present, preserved. In raising the superficial fascia in front 
of and around the saphenous opening, it v/ill be found to 



ANATOMY OF FEMORAL HERNIA. 493 

contain more or less fibrous tissue whicli connects it firmly 
to the fascia lata, especially to the surface of the falciform 
process and its crescentic border. Sometimes this connection 
between the two fascia is so intimate that in separating them 
it seems more like making an artificial division than follow- 
ing any natural line of separation. On account of its fibrous 
character, its close connection to the fascia lata, and the nu- 
merous small openings in it for the transmission of lympha- 
tics, this part of the superficial fascia has been described as a 
distinct fascia, under the name oi crihrif or m fascia. There is 
no good reason, however, why it should be so regarded or 
described. 

To raise the superficial fascia in any part of the femoral 
region without getting through the fascia lata requires a 
good deal of care, and more particularly if the subject happens 
to be fat. No student should attempt to remove it with the 
expectation of preserving the subjacent parts entire unless 
he has previously obtained a clear idea of them from books 
or previous demonstrations. The parts which require the 
most care not to injure in the dissection are, the falciform 
process in front of the femoral vessels, its crescentic border, 
Hey's ligament, and the infundibuliform sheath where it cor- 
responds to the saphenous opening, and is perforated by the 
saphenous vein. In his first dissection of this region, the 
student had better remove the superficial fascia corresponding 
to these parts piecemeal. 

The/ascm laia^ Fig. 150 (i 7), Fig. 208, is the proper invest- 
ing membrane of the thigh. It is aponeurotic in structure, 
resembling in some parts a broad tendon. It forms a common 
sheath to the muscles of the thigh, and furnishes septa which 
pass between them and separate them from each other. It 
will be referred to from time to time as the dissection of the 
thigh is continued. In the region which is now being exa- 
mined, it constitutes a most important feature in the anatomy 
of femoral hernia. An opening occurs in it just below the 
inner portion of Poupart's ligament, through which the in- 
ternal saphenous vein passes to open into the femoral vein, 
and through which the bowel escapes in femoral hernia. 
This orifice is named the saphenous opening^ Fig. 148 (20). 
The manner in which it is formed is a little complex; or, it 
is apt to appear so to the student. 

In describing this portion of the fascia lata, it must be pre- 
42 



494 THE LOWER EXTEEMITY. 

sumed that the dissector has some knowledge of the muscles 
and vessels situated beneath it, also of Poupart's ligament 
including Gimbernat's, and of the infundibuliform sheath 
of the vessels. 

It is divided into two parts, by the saphenous opening. 
The portion which is situated on the inner side of the 
opening is named the pubic or pectineal^ and, that placed 
on the outer side and above, the sartorial or iliac portion. 
Below the opening the fascia is continuous from one side of 
the thigh to the other. 

The ;9i/5/c portion is usually quite thin, and lies directly 
on the adductor longus and pectineus muscles. It is attached, 
above, to the body, the spine, and the pectineal line of the 
pubic bone ; externally, it dips down behind the infundibu- 
liform sheath, and of course behind the femoral vein and 
artery which the sheath incloses. 

The iliac portion lies on the sartorius, iliacns intern us and 
psoas magnus muscles, and the infundibuliform sheath with 
its inclosed vessels, and in front of the femoral ring. It is 
attached, above, to the anterior superior spinous process of 
the ilium, and to the lower border of the whole of Poupart's 
ligament, including Gimbernat's. Internally, it forms the 
outer and upper boundary of the saphenous opening. This 
border is curved with the concavity looking to the pubic 
side and somewhat downwards ; the term crescentic has been 
applied to it. 

That portion of the fascia which lies in front of the vessels 
and the femoral ring is named i\iQ falciform process^ while that 
portion of the process which is placed in front of the ring 
is called Seifs ligament. Hey's ligament, then, is under- 
stood to be, simply the small portion of the fascia lata 
which lies in front of the femoral ring and is attached to 
the border of Gimbernat's ligament, and, by a narrow point, 
to the pectineal line. 

It will now be seen that the infundibuliform sheath and 
the femoral vessels lie leliind the iliac and in front of the 
pubic portion of the fascia lata; and that the saphenous 
opening is formed by the division of the fascia lata into these 
two portions. 

The saphenous opening^ Pig. 148 (20), is of an oval form 
with the narrow extremity directed upwards. The lower 
boundary is named the semilunar margin^ and is formed by a 



ANATOMY OF FEMOEAL HEENIA. 495 

doubling of the fascia on itself; it is easily fonnd by trac- 
ino^ the saphenous vein upwards. The outer and upper 
boundary is formed by the crescentic border of the falciform 
process. This does not always present a well-defined mar- 
gin. It may usually be found by drawing the semilunar 
margin downwards with the forceps or tenaculum, and thus 
making it tense. The inner boundary is formed by the ex- 
ternal surface of the pectineal portion of the fascia. 

In dissecting the saphenous opening, the student must 
bear in mind that the femoral vessels are not to be exposed, 
as it would destroy the infundibuliform sheath which has not 
yet been examined. The saphenous vein perforates the 
sheath, and hence it should not be traced at this stage of the 
dissection further than to the saphenous opening. 

The parts in the abdomen should now be examined. As 
they have already been described in detail in connection 
with the other parts of the abdomen, it will only be neces- 
sary to notice them now in their relations to hernia. They 
consist of the peritoneum, the subperitoneal areolar tissue, 
'and the fasciae trans versalis and iliaca. 

The peritoneum is the most internal layer, lying next to 
the bowels. It presents a depression or fossa bounded, on 
the outer side, by a fold caused by the remains of the umbili- 
cal artery of the foetus projecting inwards, and below by the 
horizontal ramus of the pubic bone. This fossa corresponds 
to the femoral ring. 

The subperitoneal areolar tissue is placed between the peri- 
toneum and the fasciae transversalis and iliaca. It connects 
the peritoneum and these fasciae, and contains the epigastric, 
the spermatic, and the external iliac vessels, also the vas defer- 
ens, the genito-crural nerve, and lymphatics. It is not equally 
diffused between these membranes, but is more abundant in 
some places than in others. It, together with a lymphatic 
gland, fills the crural canal; this part of it forms what has 
improperly been called the septum crurale. This tissue is 
always carried down by the bowel in hernia, and is then 
converted into a well-marked membranous layer which has 
been designated Xh.Q fascia propria. This should now be care- 
fully dissected oif from the fascia3 and the other parts be- 
neath it. It will then be seen that the transversalis and iliac 
fascia) are united along Foupart's ligament from the anterior 
superior spinous process of the ilium to near the external 



496 THE LOWER EXTREMITY. 

iliac artery, tlius, closiDg the space between the ligament and 
the iliacus internus and psoas magnus muscles ; but between 
the point where the junction of the two fasciae ceases on Pou- 
part's ligament and the spine of the pubic bone, or rather, 
Gimbernat's ligament, a large opening is observed between 
Poupart's ligament in front and the os pubis behind. In- 
stead of the fasciae, however, terminating at the margin of 




A Section of the Stectctures which pass beneath the Femoral Arch.' — 1. 
Poupart's ligament. 2, 2. The iliac portion of the fascia lata, attached along the 
margin of the crest of the ilium, and along Poupart's ligament, as far as the spine 
of the OS pubis (3). 4. The pubic portion of the fascia lata, continuous at (3) with 
the iliac portion, and passing outwards behind the sheath of the femoral vessels to 
its outer border at 5, where it divides into two layers; one is continuous with the 
sheath of the psoas (6) and iliacus (7); the other (8) is lost upon the capsule of the 
hip-joint (9). 10. The anterior crural nerve, inclosed in the sheath of the psoas and 
iliacus. 11. Gimbernat's ligament. 12. The femoral ring, within the femoral 
sheath. 13. The femoral vein. 14. The femoral artery: the two vessels and the 
ring are surrounded by the femoral sheath, and thin septa are sent between the 
anterior and posterior wall of the sheath, dividing the artery from the vein, and 
the veiri from the femoral ring. 

this opening, they are prolonged downwards to the extent of 
about an inch and a half, forming a sort of a pouch open at 
the lower end for the passage of the femoral vessels. This 
pouch is divided lengthwise into three compartments or canals, 
Pig. 209 (14), by two fibrous septa which pass from its anterior 
to its posterior wall. The external iliac artery passes through 



ANATOMY OF FEMOEAL HEKNIA. 497 

tlie outer, and the external iliac vein the middle one, while 
the inner one, which is shorter than the other two, is occupied 
by subperitoneal areolar tissue and a lymphatic gland, and is 
named the crural canal. The pouch itself is the infundibuli- 
form sheath of the femoral vessels, noticed in the dissection of 
the parts below Poupart's ligament. 

The crural canal should now be examined. To do this, 
the areolar tissue and lymphatic gland, if one be present, 
must, in the first place, be removed; the finger should then 
be introduced into, and gently pushed down to the saphe- 
nous opening, having first flexed the thigh on the abdomen 
and rotated it inwards. If the thigh be now extended 
and rotated outwards, the upper part of the canal will be 
constricted by Poupart's and Hey's ligaments being made 
tense, and the effect of the position of the limb upon the 
neck of a hernial tumor distinctly understood, as well as the 
importance of placing the limb in a proper position when 
attempting to return the bowel either by taxis or after an 
operation in case of strangulation. 

The upper orifice of the crural canal is called the crural or 
femoral ring^ Fig. 209 (12). Its boundaries are, in front and 
on the inner side, Hey's ligament and Poupart's including 
Gimbernat's ligament; on the outer side, the femoral vein ; and 
behind, the pubic bone covered by a lamina of fibrous tis- 
sue. These boundaries are exterior to the proper walls of 
the canal. Dropping the terms of Hey's ligament and Gim- 
bernat's ligament, it might simply be said that the fascia lata 
and Poupart's ligament are placed in front and on the inner 
side of the upper part of the crural canal, and must be re- 
garded, when considered in their relations to the neck of a 
hernial tumor, as forming one structure. The crural canal 
cannot be said to have any external orifice, unless the saphe- 
nous vein forms one in entering the sheath of the vessels. 

There is no artery of much size in the majority of cases 
that has any direct relation to the femoral ring. There is 
usually a small anastomosing branch which crosses over the 
ring to the obturator artery. This branch is occasionally 
met with of considerable size. The obturator artery not un- 
frequently arises from either the epigastric or external iliac, 
and passes inwards to reach the upper part of the obturator 
foramen. In this case it may be placed either above or be- 
low the neck of a hernial tumor; but, if it arises from the 

42'=- 



498 



THE LOWER EXTREMITY. 



iliac artery, some distance above Poupart's ligament, it will 
have no direct relation to hernia. 

The trans versalis and iliac fasciae may now be dissected up 




After the removal of the Lower Part of the External Oblique (with 

THE exception OF A SMALL SLIP INCLUDING PoUPART'S LiGAMENt), THE LoWER 

Portion of the Internal Oblique was raised, and thereby the Transver- 
salis Muscle and Fascia have been brought into view. The Femoral 
Artery and Vein are seen to a small extent, the Fascia Lata having been 

TURNED ASIDE AND THE ShEATH OF THE BLOODVESSELS LAID OPEN. — 1. External 

oblique muscle. 2. Internal oblique. 2'. Part of same turned up. 3. Transver- 
salis muscle. Upon the last-named muscle is seen a branch of the internal cir- 
cumflex ilii artery, with its companion veins ; and some ascending tendinous fibres 
are seen over the conjoined tendon of the two last-named muscles. 4. Transversalis 
fascia. 5. Spermatic cord covered with the iufundibulifurra fascia from preceding. 
6. Upper angle of the iliac part of fascia lata. 7. The sheath of the femoral ves- 
sels. 8. Femoral artery. 9. Femoral vein. 10. Saphenous vein. 11. A vein 
joining it. 



for a short distance above the mouth of the infundibuliform 
sheath in order to trace them down as they enter into the 
formation of this sheath. In doing this, the fascia transver- 
salis will be found to be intimately connected to some apo- 



ANATOMY OF FEMORAL HERNIA. 499 

neurotic or tendinous fibres wMch arise to the outer side of 
the artery, and, arching over the mouth of the sheath, are in- 
serted into the linea pectinea; these fibres form what has 
been called the deep femoral arch. When observed from 
above they appear, in front of the sheath, to be a part of 
Poupart's ligament. When the fascia has been separated 
from these fibres, the handle of the scalpel can generally be 
carried down beneath them to the saphenous opening, and 
also to the outer side of it, so as to separate the falciform 
process of the fascia lata from the sheath. The parts in 
front of the sheath may next be divided and reflected off for 
the purpose of examining the sheath with its septa, and the 
artery and vein as they lie in it. The anterior crural nerve, 
Fig. 209 (i o), will be found four or five lines external to the 
artery, occupying a groove formed by the psoas and iliacus 
muscles. 

If the student will now review the parts which he has just 
dissected with reference to the protrusion of the bowel in 
hernia, he will have no difficulty in understanding the man- 
ner in which the protrusion takes place, and the new rela- 
tions the bowel acquires to the surrounding parts. 

He will observe that the bowel, in escaping from the cavity 
of the abdomen, first passes through the femoral ring and gets 
into the crural canal, carrying with it the peritoneum and 
the subperitoneal areolar tissue. If it remained in the canal, 
it would be called concealed femoral hernia. It does not, how- 
ever, generally stop here, but forces its way through that part 
of the anterior wall of the canal which corresponds to the 
saphenous opening in the fascia lata, and then turns upwards 
and outwards over the falciform process, and sometimes over 
Poupart's ligament, beneath the superficial fascia and the skin, 
thus forming a curve, with the concavity looking upwards, 
and the convexity downwards. 

It will be seen that the bowel is now covered, proceeding 
from without inwards; first, by the shin; secondly, by the 
superficial fascia ; thirdly, by the suh2)eritoneal areolar tissue 
or the fascia propria; and fourthly, by the peritoneityn which 
forms the sac. The first two layers are obtained outside the 
femoral canal, and the other two, one within it, and one in 
the cavity of the abdomen. 

In reducing the bowel by taxis, it should be pushed down- 
wards, backwards, and iipwards, the hnvor extremitv havino- 



500 THE LOWER EXTREMITY. 

first been placed in a proper position. In cutting a stricture 
at the upper part of the crural canal, the incision should be 
made upwards, or upwards and inwards. 

In continuing the dissection of the thigh, the integument 
must be dissected o& down as far as the tubercle of the tibia, 
both in front and on the sides. To do this, the incision, com- 
menced at the anterior superior spinous process of the ilium, 
may be extended down below the outer side of the knee, and 
then carried across the leg to the inner side. Having done 
this, the integument may be reflected from the outer to the 
inner side of the limb. 

The superficial fascia of the thigh requires no further no- 
tice. It passes over the knee, and is continuous with that of 
the leg. The saphenous vein may be traced down as far -as 
the skin has been removed. The cutaneous nerves. Fig. 208, 
as was mentioned in the previous dissection, are derived from 
the lumbar plexus, the genito-crural and the anterior crural, 
and also from the obturator nerve. 

The anterior branch of the external cutaneous nerve usually 
perforates the fascia lata about four inches below Poupart's 
ligament. It supplies the integument on the inner and ante- 
rior part of the thigh. 

The middle cutaneous nerve, a branch of the anterior crural, 
usually becomes subcutaneous four or five inches below 
Poupart's ligament. It passes down on the fore part of the 
thigh to the knee. It frequently divides into two branches, 
nearly of the same size, soon after perforating the fascia lata. 

The internal cutaneous nerve is also a branch of the anterior 
crural nerve. It perforates the fascia lata on the inner part 
of the thigh, about three inches above the knee, and then 
passes down to the internal condyle of the femur, where it 
turns outwards over the patella, and ends in the skin on the 
outer side of the knee. In its course down the thigh, this 
nerve frequently gives ofi* several branches, which perforate 
the fascia lata at different points, and become subcutaneous. 
One or two of these branches accompany the saphenous vein 
for a short distance. 

The internal saphenous nerve, Fig. 207 {e), becomes subcu- 
taneous at the inner side of the knee, and then continues as 
such down the leg, in company with the internal saphenous 
vein. Before becoming subcutaneous, it gives off* a branch, 
which is lost in the skin which covers the patella. Quite a 



ANTEKIOK PAET OF THE THIGH. 501 

large cutaneous hranch is sometimes found on the inner side of 
the knee and the upper and back part of the leg, that is de- 
rived from the obturator nerve. When this occurs, it takes 
the place of a branch of the internal cutaneous nerve. The 
cutaneous nerves of the thigh anastomose with each other. 

The superficial fascia may now be removed by first making 
an incision through it down the middle of the thigh, and over 
the patella, and then reflecting it outwards and inwards. A 
bursa mucosa^ situated in the subcutaneous areolar tissue, 
between the skin and the patella, should be observed. The 
density of the fascia, and the absence of adipose tissue in the 
vicinity of the patella, should also be noticed. However 
much adipose substance there may be above and below the 
patella, there is very little, if any, ever found in front of it. 

Tn examining the fascia lata at this stage of the dissection, 
it will be found to divide into two layers below the anterior 
superior spinous process of the ilium, to inclose the tensor 
vagincB femoris muscle^ and then to pass to the gluteus medius. 
It should not be exposed much posterior to the tensor muscle 
at present. The superficial layer may now be divided from 
the spinous process downwards, and somewhat backwards, 
to the extent of three or four inches, exposing the tensor 
vaginae femoris. 

The Tensoe YAGiNiS Femoeis, Fig. 211 (4), arises tendi- 
nous from the anterior superior spinous process of the ilium, 
and, passing downwards and backwards, is inserted^ about four 
inches below its origin, into the fascia lata ; the two layers 
which form its sheath being here united. In dissecting out 
the tensor vaginae femoris, some care is necessary not to ex- 
pose the gluteus medius and minimus muscles. Below and 
behind the insertion of the tensor vaginse femoris, the fascia 
lata is connected to the tendon of the gluteus maximus, and, 
below this, to the linea aspera and the external condyle of 
the femur. The action of the tensor vaginas femoris will 
now be easily understood. It first renders the fascia tense, 
and then rotates the thigh inwards by acting on the liuea 
aspera through the fascia. 

The vastus externus Fig. 211 (7), arises for some distance 
from the fascia lata, near its attachment to the linea aspera, 
and it will be seen, in the dissection of the posterior part of 
the thigh, that the short head of the biceps flexor arises 



502 



THE LOWER EXTREMITY. 



from the corresponding surface on the other side. This 
part of the fascia is called the external intermuscular septum. 
It separates the muscles on the outer from those on the back 
part of the thigh. Below, the fascia passes down in front of 
the knee. Internally, it is inserted into the linea aspera from 
the trochanter minor to the internal condyle. This part 
forms ^^Q^JAiternal intermuscular septum. 

As the dissection is continued, it will be found that the 
fascia lata sends in processes from its 
Fig. 211. inner surface to form sheaths for the 

different muscles, and also for the femo- 
ral vessels. If, in removing this fascia, 
the student will first look at the drawing, 
Fig. 211, he will see the muscles which 
are to be exposed, and then, by dividing 
the fascia on each muscle, and in the 
direction of its fibres, he will have no 
dif&culty in making a clear exposition of 
them. With a little care and patience, 
he will be able to do this, and, at the 
same time, preserve the principal vessels 
and nerves. 

The Sartorius, Fig. 211 (s), arises ten- 
dinous from the anterior superior spinous 
process of the ilium and from the notch be- 
low, passes obliquely downwards, inwards, 
and somewhat backwards, to the lower 
third of the thigh, and then directly down- 
wards to the inner side of the knee-joint, 
where it becomes tendinous, and, curving 
outwards round the joint, is inserted into 
the tibia just below and on the inner side 
of its tubercle. It covers the tendons of the 
gracilis and semi-tendinosus, and is con- 
nected to the deep fascia of the leg. The 
internal saphenous nerve will be seen 

The Muscles of the Anterior Femoral Region. — 1. The crest of the ilium. 
2. Its anterior superior spinous process. 3. The gluteus medius. 4. The tensor 
vaginaa femoris ; its insertion into the foscia lata is shown inferiorly. 5. The 
sartorius. 6. The rectus. 7. The vastus externus. 8. The vastus internus. 9, 
The patella. 10. The iliacus internus. 11. The psoas magnus. 12. The pectineus. 
13 . The adductor longus. 14. Part of the adductor magnus. 15. The gracilis. 




ANTERIOE PART OF THE THIGH. 



503 



Fig. 212. 



emerging between its anterior border and tbe tendon of the 
gracilis, opposite the internal condyle. It increases somewhat 
in breadth as it descends to the lower part of the thigh. Its 
fibres are the longest in the body. Its action is first to flex 
the leg on the thigh, and then the thigh on the pelvis, and, 
at the same time, draw the limb across the other. 

The gracilis may be dissected next, 
as its dissection will involve no im- 
portant vessel or nerve. 

The Gracilis, Fig. 211 (i s), arises 
by a thin, flat tendon, from the body 
and ramus of the pubic bone by the 
side of the symphysis, descends on the 
inner side of the thigh and knee-joint, 
and is inserted into the inner side of 
the tubercle of the tibia. Itdiminishes 
in width from above downwards ; its 
borders look for wards and backwards; 
and it becomes tendinous a short dis- 
tance above the knee. Its action is to 
flex the leg on the thigh and move 
it towards the opposite limb. 

The sartorius and gracilis may 
now be detached at their origins and 
turned downwards; and also the 
tensor vaginse femoris. They must 
be preserved for the purpose of re- 
placing them at a future time to 
study their relations to other parts. 
On raising the sartorius, the middle 
cutaneous nerve will be seen perfo- 
rating it. 

The next stage of the dissection 
will include the femoral artery and 
its branches, the femoral vein, and 
the branches of the anterior crural 
nerve under the fascia lata. To 
expose these satisfactorily will rc- 




A View oii' thr Anterior Crural, Nerve and Branotiks. — 1 
gcnce of the nerve under Poupart's lijijaniont. 2. Division ot 
brandies. 3. Femoral arterj'. 4. Femoral vein, 
6. Nervus sapbenus. 



Place of onier- 

tbo norve into 

Brancbes of obturator nerve. 



504 THE LOWER EXTREMITY. 

quire time and patience. They should be carefully studied 
before their dissection is commenced ; and when begun the 
scissors as well as the scalpel and the hooks will be brought 
in requisition in the removal of the areolar tissue and the 
adipose substance in which they are imbedded. 

The femoral artery and vein have already been exposed 
in the infundibuliform sheath. The anterior crural nerve 
should be sought in the sulcus formed by the iliacus and 
psoas muscles ; and when found it should be raised up and 
made tense, so that the direction of its branches may be dis- 
tinctly seen and more readily traced. 

It is better to follow out the principal branches of the 
crural nerve before commencing the dissection of the vessels. 
This is readily done with the point of the scalpel, when they 
are rendered tense, separating them partly by cutting and 
partly by tearing. They consist of cutaneous and muscular 
branches. The former were described after they became 
subcutaneous in connection with the superficial fascia. The 
middle cutaneous was divided in raising the sartorius. The 
internal cutaneous descends to the outer side of the artery 
three or four inches, and then perforates the fascia lata. In 
this part of its course it gives off several cutaneous filaments, 
some sm.all branches to the sartorius and to the sheath of the 
femoral vessels, and others to anastomose with the saphenous 
and obturator nerves. The saphenous nerve passes down on 
the outer side of the artery, but leaves it when the artery enters 
the popliteal region ; it then proceeds to the inner side of the 
knee-joint and becomes subcutaneous. In the deep part of 
its course it gives off some cutaneous and muscular branches 
and also filaments to anastomose with other nerves. 

The muscular branches require no particular description. 
They will be found supplying the muscles on the outer side 
and fore part of the thigh ; also, the pectineus, and in part 
the adductor longus, on the inner side. A large branch 
goes to the lower part of the vastus internus, which has been 
called the short saphenous nerve. 

The Femoral Artery, Fig. 206 (14), commences at a 
point a little to the inner side of the middle of Poupart's liga- 
ment, and extends to the junction of the middle and lower 
thirds of the thigh, when it passes through a tendinous 
canal formed by the adductor magnus and the vastus inter- 
nus, to enter the popliteal space. 



ANTERIOR PART OF THE THIGH. 505 

The femoral artery is accompanied by the Femoral 
Yein", which is at first placed to its inner side and on the 
same plane, but soon gets behind, and in the last part of its 
course, a little to the outer side of it. The saphenous nerve 
lies close to the outer side of it, except at its upper part. 
Small nervous twigs are usually met with either accompany- 
ing the artery, crossing it, or twining around it. 

The branches of the femoral artery to be examined next 
are the inferior external pudic and the profunda, or the deep 
femoral artery. Several small branches in the groin have 
already been dissected. 

The inferior external pudic^ Fig. 206 (le), arises near the 
profunda, sometimes from the profunda itself, passes inwards 
over the femoral vein below its junction with the saphenous, 
and the pectineus muscle to the ramus of the pubes, and 
thence to the scrotum, in the male, or to the labium exter- 
num in the female. It perforates the fascia lata near the 
pubic bone. 

The Arteria Profunda, Fig. 213 (is), arises from the 
outer and back part of the femoral, about an inch and a half 
below Poupart's ligament; the point of its origin, however, 
varies very much in different subjects. It may not be more 
than half an inch below Poupart's ligament, or it may be 
two or three inches. At first it passes backwards and some- 
what outwards, and then directly downwards to the upper 
border of the adductor longus, beneath which it continues 
down to the lower third of the thigh resting on the adductor 
brevis and the adductor magnus. It perforates the last 
named muscle and its terminal branches are distributed to 
the back part of the thigh. In the last part of its course it is 
very deep seated, running behind and nearly parallel with the 
femoral artery. It gives off' the following branches : — 

The external circumflex^ Fig. 213 (is), which frequently 
arises from the femoral artery, passes transversely outwards 
behind the rectus and in front of the psoas and iliacus mus- 
cles and divides into descending, transverse, and ascending 
branches. This artery and its branches behind and to the 
outer side of the rectus, can be traced more readily after that 
muscle has been dissected. 

The internal circumflex^ Fig\ 213 (i-j), whicli also occasion- 
ally arises from the femoral, is usually larger than the ex- 
43 



506 



THE LOWEE EXTREMITY. 



Fig. 213. 



ternal. It passes almost directly backwards between the 
pectineus and the capsular ligament of the hip -joint. It 

cannot be followed further at the 
present time. 

Besides the circumflex the pro- 
funda gives off three or iouv perfo- 
rating branches^ Fig. 190 (19), Fig. 
213 (is). These pass through the 
adductor magnus and are expended 
on the back of the thigh. Some- 
times they arise by a common trunk. 

The veins correspond to the ar- 
teries just described. The vein 
which accompanies the profunda 
artery lies between it and the fe- 
moral artery. In dissecting the 
arteries the veins may be cut 
away. The arteries should be pre- 
served until the muscles have been 
dissected, so that their relations to 
the muscles may be observed. 

The quadriceps extensor cruris 
may now be examined. As its 
name indicates it is a muscle hav- 
ing four heads. These are usually 
described as separate muscles. They 
are named the rectus femoris, the 
vasti externus and internus, and 
the crureus. They cover nearly the 
whole of the anterior and lateral 
surfaces of the femur. 

To expose these muscles divide 
the fascia lata along the middle 

A FnoNT View of the Femoral Artery, as well as of the Primitiye and 
External Iliac of the Right Side. — 1. Primitive iliac artery. 2. Internal iliac 
artery, 3. External iliac artery. 4. Epigastric artery. 5. Internal circumflex ilii 
artery. 6. Arteria ad cutem abdominis, 7. Commencement of the femoral just 
under the crural arch. 8. Point where it passes the vastus internus muscle, 9. 
Point where it leaves the front of the thigh to become popliteal. 10, Muscular 
branch to the psoas and iliacus, 11. External pudic artery cut off". 12. Origin 
of the internal circumflex. 13, 13, Profunda femoris : first 13 points to origin of 
external circumflex. 14. Muscular branch. 15,16. Artery to the vastus externus. 
17. Artery to the pectineus and adductors, 18. First perforating artery. 19, 19, 
19,19. Muscular arteries. 20. Anastomotica. 21. Superior internal articular. 22. 
Branch of superior external articular. 23. Superior external articular. 24. Infe- 
rior external articular. 25. Inferior internal articular. 




ANTERIOR PART OF THE THIGH. 507 

line of tlie thigh down to tlie patella, and dissect it off from 
the mnscles by cutting in the direction of their fibres. 

The Eectus, Fig. 211 (e), arises by two short tendinous 
heads, one from the anterior inferior spinous process of 
the ilium, and the other from the superior margin of the 
acetabulum. From this double origin it proceeds down- 
wards on the front part of the thigh to the patella, into 
which it is inserted. It is broader and thicker in the middle 
than above or below. Its tendon at first is somewhat round, 
but expands as it descends, and is prolonged much further 
on the anterior than on the posterior part of the muscle, 
while in the lower part the tendon extends further up behind 
than it does in front. The fibres pass off obliquely on both 
sides from the middle line, and hence it is called a penniform 
muscle. The action of the rectus is to assist in extending 
the leg on the thigh, or in flexing the thigh on the pelvis. 

The rectus may now be divided in the middle and turned 
upwards and downwards, and the dissection of the external 
circumflex artery completed. 

The Yastus Externus, Fig. 211 (7), arises around the 
base of the trochanter major, from the linea aspera, from the 
ridge which runs from it to the trochanter, and also from 
the external intermuscular septum of the fascia lata. It is 
inserted into the patella and the tendon of the rectus. The 
direction of its fibres increase in obliquity from above down- 
wards, the upper fibres descending almost perpendicularly, 
while the lower are nearly transverse. It is separated from 
the crureus beneath it by vessels, nerves, and areolar tissue ; 
this space should be observed with reference to the collection 
of pus in it. 

The Vastus Internus, Fig. 211 (s), is placed on the inner 
side of the thigh, and is not separated by any natural divi- 
sion from the crureus. It arises from the linea aspera and 
from a rough line extending from the linea aspera to the 
trochanter minor, and also from the internal intermuscular 
septum. It is inserted into the patella and the tendon of the 
rectus. 

The crureus^ Fig. 214 (1 5), arises from the anterior surface of 
the femur, commencing above at the anterior intertrochanteric 
ridge, and extending downwards between the origins of the 
vasti to a short distance above the condyles. It is inserted into 



508 



THE LOWEil EXTEEMITY. 



Fig. 214. 



the tendon of the rectus and into the patella. When the crn- 
reus is raised a fasciculus will be found going to the upper part 
of the synovial membrane of the knee-joint. This is called 
the suhcrureus muscle. Its action is supposed to be to draw 
the synovial membrane upwards, so that it may not be 
pinched between the articular surfaces of the joint. It should 
be observed that the crureus does 
not occupy in its origin the whole of 
the anterior surface of the femur. 

The action of the vasti and crureus 
muscles is to assist the rectus in ex- 
tending the leg on the thigh. These 
four muscles, it will be seen, are at- 
tached to the tubercle of the tibia 
through the medium of the patella 
and the ligament of the patella. 

The pectineus and the adductor 
muscles, including the lower portion 
of the psoas magnus and iliacus in- 
ternus, may now be examined. The 
last-named muscles have already been 
described. 

The Pectineus, Fig. 214 (4, s), is 
situated at the upper and anterior 
part of the thigh. It arises from the 
pectineal line, and from a triangular 
surface in front of this line, passes 
downwards, and is inserted into the 
ridge which extends from the trochan- 
ter minor to the linea aspera. ^ 

The Adductoe Longus, Fig. 214 
(e, 9, 10), lies on the inner side of the 
pectineus, with v/hich it is usually 




A View op the Deep-seated Muscles on the inside of the Thigh. — 1. Os 
ilii. 2. Capsular ligament of the hip-joint. 3. Trochanter major. 4. Origin of 
the pectineus muscle. 5. Symphysis pubis, 6. Origin of the adductor longus. 7. 
Insertion of the iliacus internus and the psoas magnus. 8. Insertion of the pectineus. 
9. Middle of the adductor longus. 10. Tendinous insertion of the adductor longus. 

11. Part of the adductor brevis seen between the pectineus and adductor longus. 

12. Adductor magnus. 13. Aperture for the passage of bloodvessels. 14. Adduc- 
tor magnus with opening for the femoral vessels. 15. Portion of the crureus. 16. 
Another opening for vessels. 17^ 18. Cut tendon of the quadriceps femoris. 19. 
Ligament of the patella. 



ANTERIOR PART OF THE THIGH. 509 

closely connected at its upper part, but separated from it below 
by a triangular areolar interspace, in which the adductor bre- 
vis is seen. It arises^ by a narrow, flat tendon, from the spine 
and body of the pubes, passes downwards, l3ack wards, and 
outwards, and is inserted into the linea aspera at the middle 
third of the femur. Near its insertion, it is connected by 
tendinous fibres to the adductor magnus and vastus inter- 
nus. It is perforated by branches of the arteria profunda 
femoris. 

The pectineus and adductor longus should now be detached 
at their origins, and carefully turned downwards for the pur- 
pose of examining the anterior or superficial branches of the 
obturator nerve, which are situated immediately behind these 
muscles. 

The obturator nerve,^ Fig. 212 (5), enters the inner and upper 
part of the thigh through the sub-pubic canal in the obtura- 
tor foramen. As it leaves the canal, or just before it leaves, 
it gives off one or two twigs to the obturator externus muscle, 
and to the hip-joint; it then divides into its superficial and 
deep branches. The former pass in front of the adductor 
brevis, and the latter behind it. The superficial branches are 
distributed to the pectineus, adductor brevis, adductor longus, 
gracilis, and the vastus intern us muscles. After passing be- 
neath the pectineus and the adductor longus, a branch pro- 
ceeds to join the plexus formed on the inner side of the thigh 
by branches derived from the internal cutaneous and saphe- 
nous nerves. Vaginal branches are also sent to the femoral 
artery. The accessory obturator nerve will be found beneath the 
pectineus muscle. This nerve reaches the thigh by passing- 
over the brim of the pelvis near the pectineal eminence. It 
usually anastomoses with the obturator nerve, and sends a 
filament to the pectineus, and one to the hip-joint. The deep 
division of the obturator nerve perforates the obturator ex- 
ternus, to which it sends filaments. It then descends on the 
adductor magnus, to which it is principally distributed. One 
branch leaves this muscle and joins the femoral artery as it 
enters the popliteal space. It terminates in articular branches 
to the knee-joint, and to the upper and back part of the leg. 

The adductor brevis and magnus muscles may now be dis- 
sected. 

The Adductor Brevis, Fig. 214 (i i), arises from the pubes 

48* 



610 THE LOWER EXTREMITY. 

below its spine, and to the outer side of the origin of the 
gracilis. It passes downwards, outwards, and a little back- 
wards, and is inserted into the upper part of the linea aspera. 
The adductor brevis should now be raised and turned 
downwards, and the deep branch of the obturator nerve, and 
the branches of the obturator artery, traced. 

The Adductor Magnus, Fig. 214 (12), is a very large 
muscle, forming a large portion of the fleshy mass on the 
inner and upper part of the thigh. It cannot be fully ex- 
amined until the back part of the thigh is dissected. It 
arises from the ramus and anterior part of the tuberosity of 
the ischium, and from the descending ramus of the pubes. 
Its fibres pass outwards and downwards, and are inserted into 
the linea aspera through its entire length, and into a tubercle 
on the inner aspect of the internal condj^le of the femur. lis 
upper fibres have nearly a transverse direction, while those 
below increase in obliquity from above downwards. The 
portion of the muscle which is inserted into the linea aspera, 
is separated from that portion inserted into the condyle by 
the femoral vessels and their sheath; its tendon is here con- 
nected to that of the vastus internus, so as to form a tendi- 
nous arch over these vessels as they enter the popliteal region. 
By observing the direction of the fibres of the inner portion 
of this muscle, it will be seen that, when it contracts, it can- 
not compress the femoral vessels. The perforating branches 
of the arteria profunda, with their accompanying veins, pass 
through openings formed in the tendon of this muscle. 

The action of the adductor muscles, including the pecti- 
neus, is to approximate the lower extremities ; they will also 
assist in rotating the thigh outwards. The pectineus and 
adductor longus may assist in flexing the thigh on the pelvis, 
or the pelvis on the thigh. 

The obturator externvs is partly brought into view when 
the pectineus and adductor brevis are turned down. It will 
be described in the dissection of the posterior part of the 
pelvis and thigh. 

The psoas magnus and iliacus internus muscles should now 
be divided and reflected downwards, so as to expose in front 
the capsular ligament of the hip-joint, Fig. 214 (2). 



THE GLUTEAL REGION. 611 



Sect. II. — The Gluteal Eegion. 

This region includes those parts which, are found on 
the side and posterior part of the pelvis. To dissect it the 
subject must be placed on its face with the pelvis raised a 
foot or more by means of blocks. It is a matter of little 
consequence in what direction the incisions are made for the 
purpose of removing the integument unless it is intended to 
remove the fascia at the same time. In this case the inci- 
sions should be made so that the gluteus maximus muscle 
may be exposed by cutting in the direction of its fibres. 

To examine the cutaneous nerves the integument must be 
dissected off and the nerves traced in the saperiicial fascia 
and fat, which usually exists in great abundance in this 
region. The nerves are derived from the last dorsal^ the 
lumbar^ and the sacral. These enter the gluteal region at 
different points. The gluteal branch of the external cuta- 
neous nerve enters it from the anterior part of the thigh just 
below the anterior superior spinous process of the ilium. 
Two branches^ one from the last dorsal and another from the 
superior musculo-cutaneous, pass over the crest of the ilium, 
the former anterior to the middle of the crest, the latter 
more posteriorly. The posterior divisions of the last two 
lumbar are distributed principally to the skin in the gluteal 
region. There are two or three derived from the posterior 
divisions of the sacral nerves ; also filaments from the lesser 
sciatic nerve. 

Beneath the superficial fascia will be found the gluteal 
aponeurosis. This is attached above and behind to the crest of 
the ilium, to the sacrum, and to the coccyx; in front and below 
it is continuous with the fascia lata. It is quite thin where 
it covers the gluteus maximus, but thick and dense over that 
portion of the gluteus medius which is not covered by the 
preceding muscle ; the gluteus medius arises partly from its 
under surface; a layer of it passes beneath the gluteus 
maximus. It is separated from the great trochanter and the 
tuberosity of the ischium by synovial capsules. 

The Gluteus Maximus, Fig. 215 (2), is the first muscle to 
be dissected in this region. To expose it an incision should 
be made through the skin and fascia, it' the skin has not been 



512 



THE LOWER EXTREMITY. 



Fig. 215. 




The Muscles of the Gltj- 

TEAL AND POSTERIOR FeMORAL 

Regions. — 1. The gluteus ine- 
dius. 2. The gluteus maxiinus. 
3. The vastus externus, covered 
in by fascia lata. 4. The long 
head of the biceps. 5. Its short 
head. 6. The semi-tendinosus. 
7, 7. The semi-membranosus. 8. 
The gracilis. 9. A part of the 
inner border of the adductor 
magnus. 10. The edge of the 
sartorius. 11. The popliteal 
space. 12. The gastrocnemius 
muscle ; its two heads. The 
tendon of the biceps forms the 
outer hamstring; and the sarto- 
rius, with the tendons of the 
gracilis, semi-tendinosus, and 
semi-membranosus, the inner 
hamstring. 



previously removed, from near the 
middle of the sacrum to a short dis- 
tance below the trochanter major. 
This incision should be made down 
to the muscle, so that its fibres or 
fasciculi, which are very coarse, 
may be distinctly seen. If the fibres 
are now made tense the student will 
have no difficulty in exposing the 
muscle by dissecting one flap up- 
wards and the other downwards, 
being careful to observe the direc- 
tion of the fibres. This muscle arises 
from the dorsum of the ilium above 
and behind the superior semicircular 
ridge, from the tubercles on the pos- 
terior surface of the sacrum, from 
the coccyx and the great sacro-sciatic 
ligament. Some of its fibres also 
arise from the aponeurosis of the 
gluteus medius. It passes obliquely 
downwards and outwards over the 
trochanter major, from which its_ 
tendon is separated by quite a large 
hursa mucosa. The lower part of the 
muscle is inserted into the rough 
line which extends from the tro- 
chanter major to the linea aspera. 
The upper part is connected to the 
fascia lata of the thigh, A hursa se- 
parates its tendon from the vastus 
externus, and not unfrequently 
another one separates it from the tu- 
berosity of the ischium. Its lower 
border is free, and forms the lower 
boundary of the nates or buttock, 
while the upper border is blended 
with the aponeurosis of the gluteus 
medius, and can be distinguished 
from this muscle only by observing 
the different direction of the fibres of 
the two muscles. When the gluteus 



THE GLUTEAL REGION. 



13 



maximus is fairly ex- 
posed and properly stu- 
died it should be care- 
fully raised by detaching 
it from its origin and 
reflecting it downwards. 
As it is raised, the glu- 
teal artery and nerve, 
and the gluteal branch- 
es of the sciatic artery 
and lesser sciatic nerve 
Avill be found entering 
the muscle upon its un- 
der surface. The glu- 
teus medius should now 
be dissected and studied. 

The Gluteus Medius? 
Fig. 216 (e), arises from 
tfce dorsum of the ilium 
between the middle and 
superior semicircular 
ridges and the crest of 
the ilium. That portion 
of it not covered by the 
gluteus maximus has a 
very thick dense aponeu- 
rosis, from the under 
surface of which many 
of its fibres arise. Its 
fibres converge to form 
a short thick tendon, 
which is inserted into the 
outer part of the tro- 
chanter major. It will 
be observed that the di- 
rection of the fibres of 
this muscle, viewed in 
relation to the hip-joint, 
is quite diflerent from 
that of the fibres of the 
preceding muscle; that 



riff. 216. 




A View of the Drep-seatep INIuscles on 
THE Posterior Part of the IIip-Joixt. — 1. 
Fifth linnbar vertebra. 2. Ilio-lumbar ligament. 3. 
Crest of the ilium, 4, Anterior superior spinous 
process of ilium. 5. Part of the fascia lata. 6. 
Gluteus medius. 7. Its lower and anterior por- 
tion. 8. Pyriformis. <.). lionielli. UK Trochanter 
major. 11. Insertion of the gluteus medius. 12. 
Quadratus femoris. 13. Part of the adductor 
ningnus. 14. Insertion of tho gluteus maximus. 
1 5. Vastus externus. 10. Long head of the biceps. 
17. Semi-mcmbranosus. 18. Semi-tendinosus. 
11). Tuber ischii. 20. Obturator internus. 2L 
Point of the coccyx. 22. Posterior coccygeal 
ligament. 23, 24. Great sacro-sciatic ligament. 
2f). Posterior superior spinous process of ilium. 
21). Posterior sacro-iliac ligament. 



514 THE LOWER EXTREMITY. 

while tliose of t]ie latter are directed generally from behind 
forwards and downwards, those of the former are directed 
not only from behind downwards and forwards, but from 
above downwards, and also from before downwards and back- 
wards. Its lower border is placed in juxtaposition with the 
pyriformis muscle, from which some care will be requisite to 
separate it. Its under surface is penetrated by branches of 
the gluteal artery and nerves. This muscle should now be 
detached from its origin and turned downwards, when the 
gluteus minimus will be brought into view. 

The Gluteus Mikimus, Eig. 219 (s), arises from the dor- 
sum of the ilium between the middle and inferior semicircu- 
lar ridges. Its fibres converge and unite in a short tendon, 
which is inserted into the anterior border of the trochanter 
major. The direction of its fibres is the same as that of the 
fibres of the gluteus medius. The capsular ligament of the 
hip-joint is placed immediately beneath this muscle. 

The action of the glutei muscles varies according as the 
pelvis or the femur is the fixed point, also according as t]»e 
three muscles act together or separately. When standing on 
one leg these muscles hold the pelvis in situ^ and thus keep 
the body in the erect position ; or they may incline it to their 
own side, or rotate it on the head of the femur. They are 
capable of rotating the limb inwards or outwards, also of 
abducting or extending it. They are concerned in walking. 
The gluteus maximus also renders tense the fascia lata. 

The following vessels and nerves should now be exa- 
mined : — 

The gluteal artery^ Fig. 217 (i), is a branch of the internal 
iliac. It escapes from the pelvis through the upper part of 
the great sacro-sciatic foramen, and appears in the gluteal 
region between the pyriformis and gluteus minimus muscles. 
It divides into a superficial and deep branches. The super- 
ficial branch passes forwards, and divides into several branches 
between the glutei maximus and medius. These are dis- 
tributed principally to the upper part of the gluteus maximus 
and the integument of this region. The deep hranches ramify 
between the glutei medius and minimus, which muscles 
they supply. One or more of these pass upwards and for- 
wards to the anterior superior spinous process of the ilium, 
where it anastomoses with the external circum^flex artery, a 
branch of the arteria profunda, and also with the external 



THE GLUTEAL KEGION. 



515 



circumflex ilii, a branch of the 
femoral artery. Other branches 
are directed towards and above 
the trochanter major. The glu- 
teal nerves are divided into the 
superior and inferior. 

The superior gliUeal nerve^ Fig. 
218 (2), is a branch of the lum- 
bo-sacral cord. It accompanies 
the gluteal artery through the 
great sacro-sciatic foramen. It 
divides into two principal branch- 
es. One of these accompanies the 
superior deep branch of the glu- 
teal artery; the other is directed 
downwards and forwards above 
the trochanter major, and termi- 
nates in the tensor vaginse femo- 
ris muscle. These nerves supply 
the glutei medius and minimus. 

The inferior gluteal nerve comes 
from the small or lesser sciatic 
nerve. It consists of muscular 
and cutaneous branches. The 
former are distributed to the glu- 
teus maximus; they penetrate its 
under surface. The cutaneous 
branches descend below the lower 
border of the gluteus maximus, 
where some filaments ascend to 



Fig. 217. 




A View of the Arteries on the Back of the Buttock and Thigh, as well 
AS ON the Back of the Ham. — 1. Gluteal artery as it escapes from the pelvis. 
2, 3, 4. Branches which it furnishes to the gluteus medius aud gluteus minimus 
muscles. 5. Small cutaneous arteries given oft' by the posterior branches of tho 
sacral arteries. 6, 6. Internal pudic, from its exit from tlio pelvis to tho root of 
the penis. 7, 7. Sciatic artery as it escapes from the pelvis to its distri- 
bution to tho biceps and semi-tendinosiis muscles, as well as its branches to 
tho gemelli, pyriformis, and quadratus femoris muscles. 8. Termination and 
distribution of internal circumflex. 9. Profunda femoris seen in the thickness 
of the adductors. 10. A branch to adductor longus and brevis. 11. First per- 
forating artery, going to vastus externus. 12. Second perforating artery. 13. 
Third perforating artery. 14. Termination of profunda femoris. 15. A branch to 
the short head of the biceps. 10. Popliteal artery. 17, 18, 19. Its articular 
branches. 20, 21. Gastrocnemial arteries. 



516 



THE LOWER EXTREMITY. 



Fig. 218. 



supply tlie integument covering tliis muscle, while otlier 

filaments are distributed to the skin below it. 

The sciatic artery. Fig. 217 (7, 7), is a branch of the internal 

iliac. It leaves the pelvis through the lower part of the 

great sacro-sciatic notch, be- 
low the pyriformis. In the first 
part of its course, it gives off 
branches to the gluteus maxi- 
mus, some of which pass through 
the muscle, and supply the in- 
tegument over it. One or more 
branches, named coccygeal, usu- 
ally perforate the great sacro- 
sciatic ligament, and ramify on 
the dorsum of the sacrum, and 
in the coccygeal region. An- 
other branch, called the comes 
nervi ischiadici^ goes to the great 
sciatic nerve, and accompanies 
it for some distance down the 
thigh. The sciatic artery, after 
giving off these branches, de- 
scends in a line midway be- 
tween the trochanter major and 
tuberosity of the ischium on 
the gemelli, the obturator in- 
ternus, and the Cjuadratus femo- 
ris muscles, which are supplied 
with branches derived from it. 
It gives off branches to anas- 
tomose with the internal cir- 
cumflex and perforating branch- 
es of the arteria profunda. 

The internal -pudic artery^ Fig. 
217 {^^^^\ another branch of the 

internal iliac, escapes from the pelvis in company with the 

sciatic, but leaves it almost immediately to wind around 

the spine of the ischium, and enter the perineum through the 

small sacro-sciatic foramen. 

The Great Sciatic or Ischiatic ;^erve, Fig. 218 (e), is a 
continuation of the sacral plexus. It is the largest nerve in 




A View of the Branches op the 
Sacral Plexus to the Hip axd 
Back of the Thigh. — 1, 1. Posterior 
saeral nerves. 2. Superior gluteal 
nerve. 3. The internal pudic nerve 
(nervus pudendalis longus superior). 
4. The lesser sciatic nerve, giving 
off the perineal cutaneous (pudendalis 
longus inferior); and 5. The ramus 
femoralis cutaneus posterior. 6. The 
great sciatic nerve. 



THE GLUTEAL REGION, 



517 



Fis;. 219. 



the body. It leaves the pelvis in company with the sciatic 
artery and the lesser sciatic nerve, and descends between 
the trochanter major and tuberosity of the ischium to the 
posterior part of the thigh. Sometimes the whole, or a part 
of it, perforates the pyriformis muscle. It usually gives off 
one or more small articular branches to the hip-joint, j^s it 
passes over the quadratus femoris, or a little below this 
muscle, branches are sent off from it to the muscles on the 
back of the thigh, including the adductor magnus. 

The lesser sciatic nerve, Fig. 
218 (4), is derived from the 
sacral plexus. As it leaves 
the pelvis it lies at the inner 
side of the great sciatic nerve, 
but gets behind it as it de- 
scends to the back part of the 
thigh. Besides the inferior 
gluteal nerve, it gives off at 
the lower part of the gluteus 
maximus the inferior long pu- 
dendal nerve. It then conti- 
nues down the limb to the 
popliteal region and the upper 
part of the leg. The inferior 
pudendal nerve passes for- 
wards below the tuberosity of 
the ischium to reach the an- 
terior part of the scrotum. 

The internal pudic and the 
inferior hemorrhoidal nerves, 
Fig. 218 (3), will be seen at 
this stage of the dissection. 




The deep Muscles of the Gluteal 

Region. — 1. The external surface of tho 

ilium. 2. The posterior surface of the 

sacrum. 3. The posterior saero-iliac 

passing around the spine of ligaments. 4. The tuberosity of the 

tl^o icr.l-.in-.Kv. or^/I +l.r.^i..vl. +1.^ ischiuui. 5. Thc grcat Or postorior sa- 

cro-pciatic ligament. 6. The small or 
anterior saero-scialic ligament. 7. The 
trochanter major. 8. The gluteus mi- 
nimus. 9. The pyriformis. 10. Tho 
gemellus superior. 11. The obturator 
intornus, passing out of the lesser 
sacro-sciatic foramen. 12. The gemellus 
inferior. 13. The quadratus femoris. 
14. The upper part of tho adductor mag- 
nus. 15. Tlie vastus extornus. 10. Tho 
biceps. 17. The gracilis. IS. The se- 
mi-tendinosus. 



the ischium and through the 
sn^all sacro-sciatic foramen to 
enter, in company with the 
internal pudic artery, the pe- 
rineum. 

The following group of 
small muscles may now be 
examined as they appear in 
the dissection of this region. 



44 



518 THE LOWEK EXTREMITY. ' 

They will be found to occupy nearly tlie same plane with 
each other and with the gluteus minimus, except the obtu- 
rator externus. 

,^ Before commencing the dissection of them, the student 
should be particular to see that the limb is rotated inwards 
and fastened in this position so that the muscles shall be kept 
tense. 

The Pyriformis, Fig. 219 (9), lies along the lower border 
of the gluteus medius, and not unfrequently some care is re- 
quired to find the line which separates them. It arises with- 
in the pelvis from several of the spaces between the anterior 
sacral foramina and from the contiguous portion of the ilium, 
also from the great sacro-sciatic ligament. Its fibres con- 
verge as they pass outwards and somewhat backwards to be 
inserted by a round tendon into the fossa on the upper and 
back part of the great trochanter. This muscle is sometimes 
perforated by the great sciatic nerve, or by a portion of it. 

The Gemellus Superior, Fig. 219 (10), is a small muscle 
placed immediately below the pyriformis. It arises from the 
spine of the ischium, and, passing horizontally inwards, is 
inserted into the trochanter major close to the pyriformis. It 
is sometimes wanting. 

The Gemellus Inferior, Fig. 219 ( 2), arises from the 
tuberosity of the ischium near the attachment of the great 
sacro-sciatic ligament. It is inserted also into the trochanter 
major. It is usually larger than the gemellus superior. 

The Obturator Internus, Fig. 219 (n), will be found 
placed between the two gemelli occupying the small sacro- 
sciatic foramen. The principal part of this muscle is situated 
within the pelvis, and will require for its complete dissection, 
as well as that of the pyriformis, a section of the pelvic 
parietes to be made. 

It arises from the internal surface of the innominatum 
around the obturator foramen, from the obturator ligament 
and from the outer surface of the aponeurosis v/hich covers 
this muscle. Its fibres converge, pass downwards and out- 
wards through the small sacro-sciatic foramen and terminate 
in a tendon, which is inserted into the trochanteric or digital 
fossa in common with the gemelli. The gemelli, especially 
the inferior, and the obturator internus are frequently so 



THE GLUTEAL REGION. 619 

blended together for some distance from their insertion as to 
seem to form but one muscle. With a little care, however, 
the student will generally be able to separate them with the 
handle of the scalpel near the small sacro-sciatic foramen. 

In passing through this foramen the tendon of the obtu- 
rator is reflected over a trochlear surface, which, as well as 
the tendon itself, is covered by synovial membrane and kept 
constantly lubricated with synovial fluid. 

The QuADRATUS Femoris, Fig. 219 (i 3), situated just be- 
low the inferior gemellus, arises from the posterior border of 
the tuberosity of the ischium, and passing horizontally out- 
wards, is inserted into the linea quadrati, a rough line on the 
great trochanter. It is a square-shaped muscle, having its 
fibres nearly parallel to each other. It is separated from the 
upper border of the adductor magnus by the internal circum- 
flex artery^ which should now be examined in the terminal 
part of its course. This artery, by its anastomosis with the 
sciatic, establishes a connection between the profunda femoris 
and the internal iliac artery. 

The Obturator Externus is exposed posteriorly by 
raising the quadratus femoris. It arises from the external 
surface of the obturator ligament, and from the bone around 
the obturator foramen. Its fibres converge and terminate in 
a tendon which passes horizontally outwards to be inserted 
into the lower part of the digital fossa, just below the inser- 
tion of the gemelli and the obturator intern as. 

The action of the last six muscles is very similar. They 
rotate the limb when it is extended, outwards, but abduct it 
in the sitting posture. When the limb is fixed, as in stand- 
ing on one foot, they act on the pelvis. 

In raising these muscles, several small nerves will be ob- 
served penetrating them. 

The nerve for the obturator internvs arises from the sacral 
plexus, winds around the spine of the ischium, and passes 
through the small sacro-sciatic foramen to reach the muscle. 

The nerve for the quadratus femoris arises from tlie sacral 
plexus, passes downwards underneath the gemelli and obtu- 
rator internus, giving oft' in its course filaments to the hip- 
joint. Before terminating in the quadratus femoris, it sends 



520 THE LOWER EXTREMITY. 

a small brancli to the gemellus inferior. Tlie gemellus supe- 
rior receives a nerve directly from tlie sacral plexus. 

The obturator externus is supplied with branches from 
the obturator nerve, which is derived from the third and 
fourth lumbar nerves. 

Having completed the dissection of the parts in the glu- 
teal region, the student should now replace the muscles and 
study their relations to the hip-joint and to the vessels and 
nerves. The prominent points which can be seen or felt in 
this region in the living subject should be observed with re- 
ference to luxation of the head of the femur and the ligation 
of the arteries. The exact position of the trochanter major 
and the tuberosity of the ischium and their relations to the 
sacrum and ilium, should be carefully noted. It will have 
been seen that the principal arteries are the gluteal, the 
sciatic and the internal pudic. The position of each one 
of these vessels may readily be ascertained by observing its 
relations to the posterior inferior spinous process of the ilium, 
the tuberosity of the ischium, and the trochanter. 

As the dissection of the ligaments of the vertebral column 
should be made in connection with those of the pelvis, and 
as this cannot well be done until the external parts of the 
pelvis have been dissected, the dissection of the hip-joint is 
included with that of the others. 



Dissection of the Hip-Joint. 

The hip-joint is formed by the acetabulum of the os inno- 
minatum and the head of the femur. It is a ball and socket 
joint. At the lower part of the acetabulum is a notch occu- 
pied by the ligamentum teres and by the vessels that enter 
the joint; just above this notch, and in the bottom of the 
cavity, there is a depression occupied by adipose substance 
and loose synovial membrane ; the rest of the acetabulum is 
covered by cartilage. The head of the femur forms the seg- 
ment of about four-fifths of a globe. It is covered by car- 
tilage, except a small spot just below its centre, which gives 
attachment to the ligamentum teres. The ligaments of this 
joint consist of the capsular^ the cotyloid^ the round, the trans- 
verse^ and the ilio-femoral. The last two scarcely deserve to be 



DISSECTION OF THE HIP-JOINT. 



521 



Fig. 220. 



considered separate ligaments; the transverse properly be- 
longs to the cotyloid, and the ilio-femoral to the capsular. 

The Capsular or Orbicular Ligament, Fig. 220 (s), 
like that of the shoulder-joint, completely surrounds the ar- 
ticulation ; its fibres are not, however, like those of that liga- 
ment, intermixed with the tendons of surrounding muscles. 
Above and in front it is thicker and stronger than it is 
behind and below. Externally it is composed of longitu- 
dinal fibres which are parallel to each other, and internally 
of fibres that run in different directions, and interlace with 
each other ; by this arrangement of its fibres the strength of 
the ligament is very much increased. Its superior attach- 
ment embraces the circum- 
ference of the acetabulum, 
from the margin of which, 
excepting the portion formed 
by the transverse ligament, 
its fibres are prolonged for 
some distance on the bone; 
its inferior attachment sur- 
rounds the neck of the femur, 
but not so as to include the 
whole of it within the joint; 
the principal part excluded is 
situated between the trochan- 
ters and above the posterior 
intertrochanteric ridge. This 
should be noticed with refer- 
ence to fractures, as it allows 
of a fracture of the neck oc- 
curring partly within and 
partly without the capsular 
ligament; in which case, by 
proper treatment, osseous 
union may be obtained. 
The length of the inner and 
lower part of the ligament 
is greater than the distance 
between the corresponding 
points of attachment; hence 




The Ligaments op the Pelvis axd 
Hip-joint. — 1. The lower part of the an- 
terior common liojament of the vertebra?, 
extending downwards over the front of 
the sacrum. 2. The sacro-vertebral liga- 
ment. 3. The ilio-vcrtebral ligament. 
4. The anterior sacro-iliac ligament. 5. 
The obturator ligament. 0. Poupart's 
ligament. 7. (Jimbernat's ligament. S. 
The capsular ligament of the hip-joint. 
9. The ilio-femoral or accessory liga- 
ment. 



W 



522 THE LOWEE EXTEEMITY. 

there is generally a looseness in this part of the ligament 
which admits of a proportionate degree of abduction of the 
limb. When the capsular ligament is divided, there will be 
observed fibres, intermixed with areolar tissue, extending 
from the root of the cervix to the margin of the articular 
surface of the head of the bone; they seem to be a con- 
tinuation of the fibres of the capsular ligament reflected 
over the cervix, for which they form, with the areolar tissue, 
quite a thick sheath or covering, especially on the upper 
and anterior part of it. In a fracture of the neck within the 
capsule this fibro-areolar tissue might, no doubt, contribute 
largely to the formation of an osseous union. It would not 
only furnish a nidus in which callus might be formed, but 
it would be a medium for the transmission of vessels to the 
head of the bone; in the latter case it would co-operate with 
the ligamentum teres. 

The ilio-femoral or accessory ligament^ Fig. 220 (9), consists 
of a fasciculus of fibres, which arises from 'the anterior infe- 
rior spinous process of the ilium, passes obliquely downwards 
and inwards, and, spreading out, is inserted into the anterior 
intertrochanteric ridge. It strengthens that portion of the 
capsular ligament to which it corresponds. On the inner 
side of this fasciculus an opening is sometimes noticed which 
forms a communication between the bursa that is placed 
beneath the psoas and iliacus internus muscles and the cavity 
of the joint. 

The Cotyloid Ligament, Fig. 221(6), surrounds the 
margin of the acetabulum or cotyloid cavity. It is of a tri- 
angular form, presenting three sides ; one of these, the base, 
is adherent to the bone ; the other two are covered by syno- 
vial membrane, and correspond, the one with the head of the 
femur, and the other with the capsular ligament. It is not a 
proper ligament, but a fibro-cartilage, the cartilage increasing 
in quantity from the apex or free edge to the base, where 
there is but little fibrous tissue. It is separated by a groove 
from the articular cartilage which lines the acetabulum. The 
fibrous portion of it is continued across the notch at the 
lower part of the cavity; this part of the cotyloid ligament, 
together with other fibres that arise from the sides of the 
notch, constitute the Tkansvekse Lig-ament. By means of 
this arrangement, the notch is converted into a foramen for 



DISSECTION OF THE HIP-JOINT. 



623 



the transmission of vessels to the interior of the joint. What 
is called the transverse ligament is essentially a part of the 
cotyloid ligament; the addition of a few fibres which interlace 
with each other, and the fact of its subtending the notch 
does not entitle it to be considered a distinct ligament. The 
cotyloid ligament increases the depth of the acetabulum, and 
diminishes the diameter of its orifice by the edge being in- 
clined inwards towards the centre ; this constriction is seen 

Fig. 221. 




Ligaments op the Pelvis and Hip-Joint. — The yiew is taken from the 
SIDE. — 1. The oblique sacro-iliac ligament. The other fasciculi of the posterior 
sacro-iliac ligaments are not seen in this view of the pelvis. 2. The great sacro- 
sciatic ligament. 3. The small sacro-sciatic ligament. 4. The great sacro-sciatio 
foramen. 5. The small sacro-sciatic foramen. 6. The cotyloid ligament of tho 
acetabulum. 7. The ligamentum teres. 8. The cut edge of the capsular ligament, 
showing its extent posteriorljs as compared with its anterior attachment. 9. Tho 
obturator membrane only partly seen. 

by the retention of the head of the femur in the cavity after 
the capsular ligament has been completely severed. 

The Interarticular Ligament, or Ligamentum Teres, 
Eig. 221 (7), extends from the depression situated just be- 
low the centre of the head of the femur to the cotyloid notch, 
to the edges of which it is attached by two distinct fasciculi. 
It is not round, but of a triangular form, its narrow end 
being attached to the femur. It is from an inch to an inch 



524 THE LOWER EXTREMITY. 

and a quarter in lengtli; the head of the femur may be 
luxated downwards without this ligament being ruptured, 
but not upwards. It is loosely covered by synovial mem- 
brane. The ligament varies very much in size in different 
subjects. Sometimes it is entirely absent. Its principal use 
seems to be to conduct bloodvessels to and from the head of 
the femur, to the proper nutrition of which its presence is 
sometimes of the greatest importance. The depression or 
fossa, extending upwards from the notch in the bottom of 
the acetabulum, is occupied by a mass of fat, sometimes 
denominated a synovial gland. It allows vessels and nerves 
to enter the joint, and protects them against pressure from 
the head of the femur. Although called a gland, it has none 
of the characteristics of a gland. 

The Synovial Membrane of the hip-joint lines the whole 
of the internal surface of the articular cavity, and surrounds 
the interarticular ligament. It is sometimes prolonged, as 
was before mentioned, into a bursa placed between the cap- 
sular ligament and the psoas and iliacus internus muscles. 
It not unfrequently presents folds on the neck of the femur, 
which may take 'the place in part of the round ligament in 
transmitting bloodvessels to the head of the femur. 

The student should attentively observe all the prominent 
points connected with, and in the vicinity of the hip-joint; 
such as the crest of the ilium, the trochanter major, the pubes, 
and the sacrum and coccyx. The relation of the trochanter 
to the other points when the limb is placed in different posi- 
tions, as flexed, extended, abducted, and rotated both inwards 
and outwards, should be noted. It is in the dissecting 
room, with the subject before him, that the student should 
prepare himself to diagnose in diseases, fractures, and luxa- 
tions involving the hip-joint. It is here that he can measure 
for himself the distances between the different prominent 
points, and note the elevations and depressions as they are 
found in their normal condition, and then calculate the various 
changes which may occur from disease or injuries. He should 
be able, before he leaves the hip-joint, to place his finger on 
any point either in front of it or behind it, on the outer 
side or inner side of it, and specify each muscle, or any ves- 
sel or nerve that may lie between that point and the cavity 
of the joint. The articulation is completely surrounded by 
muscles. Thus in front are found the iliacus internus, psoas 



DISSECTION OF ARTICULATIONS OF VERTEBRA. 525 

magnus, and rectus femoris ; on the inner side, the pectinens, 
obturator externus, gracilis, and the adductors ; above or 
on the outer side, the glutei and tensor vaginas femoris 
muscles ; behind, the pyriformis, gemelli, obturator externus, 
and the quadratus femoris. 



Dissection of the Articulations of the Yertebr^. 

The vertebra are connected above to the occipital bone, 
laterally to the ribs, and below to the pelvis. The costo- 
vertebral articulations are described in connection with the 
dissection of the thorax; the articulation of the vertebrae with 
the pelvis is described with the pelvic articulations. It is 
proposed now to examine the articulations of the vertebrae 
with each other, and with the cranium. The proper mode 
of making the dissections will be clearly indicated by the 
accompanying drawings. The ligaments which the vertebrae 
have in common should be examined first. They are the 
following : — 

The Anterior Common Yertebral Ligament, Fig. 220 
( 1 ), is placed in front and on the sides of the bodies of the 
vertebrae, extending from the axis to the sacrum. It presents 
a pearly white appearance, is thicker in the dorsal than in the 
cervical or lumbar regions, and divided into a central and 
two lateral bands, the latter being separated from the former 
by a series of foramina on each side, for the transmission of 
vessels, especially veins. It adheres very closely to the inter- 
vertebral substance and margins of the bodies of the verte- 
bras, while it is very loosely connected to the transverse 
grooves on the bodies. It is composed of fibres which vary 
in length, diminishing from the superficial to the deep-seated ; 
the latter extend merely from one vertebra to another, while 
the former pass over four or five vertebrjB. It is thicker 
where it corresponds to the grooves on the bodies of the ver- 
tebrae than it is elsewhere. The tendons of several muscles 
are blended more or less with it in diftcrent sections of the 
vertebral column. 

The Posterior Common Yertebral Ligament, Fig. 
222 (3), is placed in the anterior part of the spinal canal, 



526 



THE LOWER EXTREMITY. 




Fig. 222. extending from tlie occiput to the sac- 

rum. It is narrower opposite the body 
of each vertebras than it is opposite to 
the intervertebral substance. It is 
thicker and more compact than the an- 
terior ligament ; its connection, however, 
with the bodies of the vertebrae and the 
intervening fibro-cartilage is nearly the 
same as that of the anterior. A plexus 
of veins with areolar tissue separates it 
from the body of each vertebra. It 
diminishes in width from above down- 
wards. The length of its fibres vary 
in the same manner as they do in the 
preceding ligament. The dura mater 
adheres loosely to its posterior sur- 
face, being connected to it by areolar 
tissue. 

The Intervertebral Substance or 
Ligaments, Fig. 223, Fig. 224, are placed 
between the bodies of all the vertebrae 
except the first two. Each one consists 
of fibro-cartilage which has the form of 
the space that it occupies. As the 
bodies of the vertebrae vary in shape 
so does the intervertebral substance. 
It is usually thicker in the centre than 
at the circumference. It adheres so 
closely to the bone that the latter will 
break before the former will separate from it. It also pos- 
sesses great strength in itself. Each one consists of lamellae 
which are more numerous in front and on the sides, in the 
cervical and lumbar regions, than behind; the reverse is true 
in the dorsal region ; they are thicker before than behind in 
the two regions first-named, while the opposite is true in the 
dorsal region. The anterior convexities of the column in 
the cervical and dorsal regions are said to be due principally 
to the thickness of the intervertebral substance, while the 
concavity in the dorsal region is attributed to the vertebrae. 
The heads of the ribs articulate. Fig. 144 (4), with the iuter- 



A Posterior view of 
THE Bodies of three Dor- 
sal Vertebrae, connect- 
ed by (1, 1). THEIR Inter- 
vertebral Substance. — 
The laminae (2, 2) have 
been sawn through near the 
bodies of the vertebrae, and 
the arches and processes 
removed, in order to show 
(3) the posterior common 
ligament. A part of one 
of the openings in the 
posterior surface of the 
vertebra;, for the transmis- 
sion of the vena basis vei'- 
tebrae, is seen at 4, by the 
side of the narrow and 
unattached portion of the 
ligament. 



DISSECTION OF AETICULATIONS OF VEETEBKiE. 527 



Fig. 223. 



vertebral substance, which also assists in forming the inter 
vertebral foramina. 

If a section of the interverte- 
bral substance be made, it will 
be found to consist, Fig. 224 (3), 
principally of a soft pulpy sub- 
stance in the centre, and of thin 
layers or laminae of fibro-car- 
tilage externally. The general 
arrangement of the laminae are 
concentric, one being placed 
within another ; some of them 
interlace with each other. They 
are connected together by fibres, 
which extend from one lamina 

to another. In proceeding from a Lumbar Vertebra, with a Hori- 
tliP Pi-rr-nmfprPnf^P tnAsrnTTl<a iha zo^^tal Section of Intervertebral 

tne circumierence towaras tne substance (i, i), above it.— At the 

centre, the number and com- circumference (l, l). the concentric ar- 
pactneSS of the laminae dimi- yangement of the la^-ers of the latter 
^ ■ I t ^ 1 IS shown, and m the middle (2) the 

nish, tne pulpy matter and puipy substance is indicated. 




Fig. -224. 




A Vertical Section of two Vertebr.e. and the Substance intf-rvosf.p be- 
tween THEIR BOBIFS. — The direction of the fibres of the intervertebral substance 
is displayed. 1,1. Fibres curved outwards. 2,2. Those curved inwards. 3. Pulpy 
substance in the middle. 



areolar tissue taking the place of them. There are fewer 
of them behind than in front and on the sides. The 
fibres which compose the lamini-e are firmlj' attached above 



528 



THE LOWER EXTREMITY. 




Two LuMBAE Vertebra with the 
Intervertebral Substance are 
SEEX from before. — By removing a 
portion of one layer (1) of the latter, 
another layer (2), is partly exposed, 
and the oblique direction of their 
fibres is made manifest. 



and below to tlie vertebrae, but not at opposite points, as 

they have, especially those of 
the onter laminse, an oblique 
direction, Fig. 225 (i, 2); they 
extend from the right to the left 
or from the left to the right, ac- 
cording as they are on the right 
side or left side of the median 
line, and according to the lamina 
that is examined, as in every 
alternate one their direction is 
reversed, so that the fibres of any 
two contiguous laminse decus- 
sate with each other. They are 
also curved. Fig. 224 (1, 2), those 
situated externally, outwards, 
and those internally inwards. 
When the spine is lengthened 
and the vertebra separated fur- 
ther from each other, both the obliquity and the curvature of 
the fibres are diminished. The same thing takes place on 
the side of the convexity when the spine is bent, and also on 
one side or the other when the spine is twisted. 

The central pulpy matter is constantly compressed, as is 
shown when a vertical section of two vertebra including the 
intervertebral substance is made, it immediately forming a 
projection beyond the surrounding cut surface. The same 
fact is shown by pushing an awl in between two vertebrae, 
when it will be forced partly back again. The expansion 
will be greater when the preparation has been for some time 
macerated or soaked in water. The property of elasticity 
which it possesses in so large a degree is an exceedingly 
important element in the construction of the vertebral 
column. 

The intervertebral substance is more abundant between 
the cervical and lumbar vertebrse than between the dorsal, 
hence these portions of the column possess a greater degree 
of mobility than the dorsal. In the aggregate, this substance 
forms about one-fourth part of the length of the spine be- 
tween the axis and the sacrum. 

In old age the intervertebral substance possesses less elas- 
ticity, being dryer and less in bulk. The reverse is true in 



DISSECTION OF ARTICULATIONS OF VERTEBRA. 529 



the young. The uses of this substance in the spinal column 
will be readily understood when its structure has been pro- 
perly examined. While it assists in forming the parietes of 
the spinal canal, the intervertebral foramina, and the costo- 
vertebral articulations, and while it holds the bodies of the 
vertebras securely in their proper place and diminishes the 
force of shocks transmitted to the brain, it allows a sufficient 
degree of mobility to every part of the column in which it 
is found, and, at the same time, prevents any undue motion 
taking place in it. 

The connection of the vertebrae by their oblique processes 
is very different from that which has been observed between 
the bodies. The oblique processes have articular facets, 
which are covered by a thin layer of cartilage and by 
synovial membrane, and articulate with those of the adjacent 
vertebrae. They are connected by imperfect capsular liga- 
ments^ which are rather longer in the neck than in the dorsal 
and lumbar regions. 

The LiGAMENTA SuB-FLAVA, Fig. 226 (i), are composed of 
yellow elastic fibres, arranged in 
dense, compact laminae, which oc- 
cupy the spaces between the arches 
or laminae of the vertebrae. The 
fibres are longer than the spaces 
between the arches, for they extend 
a short distance on the anterior 
surface, of the lamina. They form 
the parietes of the spinal canal be- 
tween the arches as far forwards as 
the roots of the transverse pro- 
cesses. They are thicker posteriorly 
than laterally, and more distinct in 
the lower than in the upper part of 
the column. They are not found 
in the space between the occiput 
and the atlas, or between the atlas 
and the axis. They are strong and 
elastic; they assist the muscles in 
keeping the column in an erect position and in restoring it 
to this position when it has been Hexed. 

The SuPRA-spiNous Ligament, Fig. 14:5(],i), connects 
45 



Fig. 226. 




An Internal A'iew of thk 
Arches ok three Vertebr.e. — 
To obtain tliis view the laiuinjv 
have been divided through thoir 
pedicles. 1. One of the liga- 
nienta subflavn. 2. The capsu- 
hxr liganicut of one side. 



530 THE LOWER EXTREMITY. 

the ends of the spinous processes of the vertebrae, including 
the occipital bone above, and the sacrum below. Between the 
occiput and the seventh cervical vertebra it forms what is 
called the ligamentum nuchse. This is connected by slips to 
the spinous processes of all the cervical vertebrae except the 
first. It varies much in size. Situated in the median line, 
it is connected Avith the teudons of several muscles in this 
region, and can be distinguished from them only by the 
direction of its fibres. The same is true of the supra-spinous 
ligament below this, which is much larger and stronger in 
the lumbar region than in the dorsal. 

The Inter-spinous Ligaments extend between the spinous 
processes of the dorsal and lumbar vertebrae. They are thin 
and membranous in the dorsal region, but quite thick and 
strong in the lumbar region. They are intimately connected 
with the tendons of the extensor muscles of the back. 

The Inter-transverse Ligaments are found only in the 
lower part of the dorsal region and in the lumbar region. 
Their use seems to be as much to give attachment to the 
muscles as to connect the bones. These, as well as the ob- 
lique, the supra-spinous, and the inter-spinous, are inelastic. 

The occipital bone is connected to the atlas by an anterior 
and a posterior ligament, and two on each side. 

The Anterior Occipito-atlantal Ligament, Fig. 227 
(1,2), may be said to consist of two, a round or superficial, 
and a broad or deep-seated one. Both of them extend from 
the anterior border of the occipital foramen to the anterior 
arch of the atlas. The superficial consists of a thick, strong, 
round fasciculus, which forms quite an elevation in the me- 
dian line; it is inserted into the tubercle on the anterior 
arch of the atlas. The deep-seated is broader than, but not 
so thick, as the superficial. 

The Posterior Occipito-atlantal Ligament, Fig. 228 
(3), connects the posterior margin of the occipital foramen 
to the posterior arch of the atlas. It is broad and thin. 
The vertebral arteries and sub-occipital nerves pass through 
it. The dura mater adheres closely to its inner surface. 

Each condyle of the occipital bone is joined to the cor- 
responding oblique process of the atlas by a Capsular Liga- 
ment, Fig. 228 (4,4.) This ligament is much thicker ex- 



DISSECTION OF AKTICULATIONS OF VERTEBRA. 531 

ternally and anteriorly than it is elsewhere. It allows con- 
siderable motion to these articulations. A synovial membrane 

Fig. 227. 




An Anterior View of the Ligaments connecting the Atlas, the Axis, ani> 
THE Occipital Bone. A Transverse Section has been carried through the 
Base of the Skull, dividing the Basilar Process op the Occipital Bone 
AND THE Petrous portions of the Temporal Bones. — 1, The anterior round 
occipito-atlantal ligament. 2. The anterior broad occipito-atlantal ligament. 3. 
Thecommencementof the anterior common ligament. 4. The anterior atlauto-axoid 
ligament, which is continuous inferiorly with the commencement of the anterior 
common ligament. 5. One of the atlanto-axoid capsular ligaments ; the one on the 
opposite side has been removed, to show the approximated surfaces of the articular 
processes (6). 7. One of the occipito-atlantal capsular ligaments. The most exter- 
nal of these fibres constitute the lateral occipito-atlantal ligament. 

lines the inner surface of each ligament, and covers the 
articular cartilage inclosed by the ligament. 

Fiff. 228. 




The Posterior Ligaments of the Occtpito-atloid, and Atlanto-axoid Arti- 
culations. — 1. The atlas. 2. The axis. .'?. The anterior ligament of the occipito- 
atlantal articulation. 4, 4. The capsular and lateral ligamouts of this articulation. 
6. The posterior ligament of the atlanto-axoid articulation. C\ 6. Its capsular 
ligaments. 7. The first of the ligauionta subtlava, passing between the axis and tho 
third cervical vertebra. 8, 8. The capsular ligaments of those vertobnv. 



532 



THE LOWER EXTREMITY. 



The Lateral Occipito-atlantal Ligamekt, Fig. 228 
(4}, connects the transverse process of the occipital bone to 
the transverse process of the atlas. It is quite a thick, strong, 
ligamentous cord. By its connection with a ligamentous 
fasciculus, which is attached to the petrous portion of the 
temporal bone, a fibrous canal is formed for the transmission 
of the large vessels and nerves at the base of the skull. 

The occipital bone is connected to the axis by four liga- 
ments; three of which are attached to the odontoid process, 
and one to the body of the axis. 

Fig. 229. 




The Upper Part of the Vertebral Canal, opened from behind in order to 
SHOW the Occipito-axoid Ligament. — 1. The basilar portion of the sphenoid 
bone. 2. Section of the occipital bone. 3. The atlas, its posterior arch removed. 
4. The axis, the posterior arch also removed. 5. The occipito-axoid ligament, ren- 
dered prominent at its middle by the projection of the odontoid process. 6. Lateral 
and capsular ligaments of the occipito-atlantal articulation. 7. Capsular ligament 
between the articulating processes of the atlas and axis. 

The Occipito-axoid Ligament, or Apparatus Liga- 
mentosus Colli, Fig. 229 (5), is placed beneath the dura 
mater, and extends from the lower part of the basilar fossa 
of the occipital bone downwards to the body of the axis, 
where the central part of it is continuous with the posterior 
common spinal ligament. The lower part of this ligament 
may be divided into three fasciculi or bands, two of which 
are situated laterally, and are continued down to the third 
or fourth cervical vertebrae. 

The Odontoid or Moderator Ligaments connect the 
odontoid process with the sides of the occipital foramen. 
They consist of thick, round fibrous cords, one on each side, 
which have an oblique direction from below upwards and 



DISSECTION OF AETICUL ATIONS OF VERTEBRA. 533 

outwards. They have been called moderator or check liga- 
ments, from their regulating the rotatory motion of the head 
on the axis. What is called the middle ligament consists of a 
few ligamentous fibres that pass from the summit of the odon- 
toid process to the anterior border of the occipital foramen. 

The atlas and axis are connected together by five liga- 
ments. 

The Anterior, Fig. 227 (4), and Posterior, Fig. 228 (5), 
Atlanto-axoid Ligaments are placed between the ante- 
rior and posterior arches of the atlas and the corresponding 
portions of the axis. The anterior is attached below, to the 
base of the odontoid process, and on each side of it, to the 
body of the axis, where it is continuous with the anterior 
common ligament. The posterior ligament corresponds to 
the ligamenta sub-flava ; below it is attached to the upper 
borders of the laminae of the axis. 

Fig. 230. 




A Posterior View of the Ligaments connecting the Atlas, the Axis, and 
THE Occipital Bone. The Postioriou taut op the Occipital Bone has been 

SAWN AWAY, and THE PoSTKRIOR ArCHES OF THE AtLAS AND AxiS RKJfOVED. 1. 

The superior part of the occipito-axoid ligament, which has been cut away in order 
to show the ligaments beneath. 2. Tiie transverse ligament of the atlas. 3.4. Tho 
ascending and doseonding slips of the transverse ligament, which have obtained for 
it the title of cruciform ligament. 5, One of tho odontoid ligaments; the other 
ligament is seen on the opposite side. 6. One of tho occipito-atlantal capsular liga- 
ments. 7. One of tho atlanto-axoid capsular ligaments. 

There are two Capsular Ligaments, Fig. 230 (7), one 
for the oblique processes on each side. Each is composed 
of straight and oblique fibres, and is thicker anteriorly 
than at any other part. Tliey are of sufficient length to 
admit of rotatory, as well as several other movements, to 
the head. They are lined by synovial meiubraues, which 

45-^- 



534 THE LOWER EXTEEMITY. 

also cover tlie articular cartilages found on tlie oblique pro- 
cesses. 

The articulation of tlie odontoid process witli the anterior 
arch of the atlas consists of a small concave facet on the former, 
and a corresponding convex one on the latter. Both of these 
are covered with cartilage and synovial membrane; they are 
also surrounded by a few ligamentous fibres, which form a 
sort of capsular ligament. 

Fig. 231. 




A View of the Atlas prom above. SHowiK^€f the Transverse Ligameht, 
"WITH Fragments of its Appendages. — 1. The space for the odontoid process. 2. 
The transverse ligament. 3. Space for the spinal cord, 4, 4. Articular processes; 
on the left one a remnant of the capsular membrane is seen. 

Posteriorly, the odontoid process articulates with theTEANS- 
VERSE Ligament, Fig. 231 (2). This hgament consists of a 
strong fasciculus of fibres which are attached to the inner 
sides of the lateral masses of the atlas. Its counection with 
the odontoid process is similar to that between the latter and 
the anterior arch of the atlas, a smooth concave articular 
facet being found on the anterior surface of the ligament, and 
a corresponding one on the posterior surface of the process. 
The synovial membrane, which lines this cavity, extends 
upwards on the process to near its summit. The ring, that 
is formed by the parietes of these articulations, has a smaller 
orifice below than above, being adapted to the shape of the 
odontoid process, so that the process will be retained in situ 
after all the other connections between the atlas and axis, or 
between these and the occipital bone have been cut away. 
From the upper edge of the transverse ligament a layer of 
fibres passes upwards, to be inserted into the anterior margin 
of the occipital foramen; and another layer of fibres from 
the inferior margin descends to be attached to the axis. The 
term cruciform has been applied to the transverse ligament, 
including the vertical fibres attached to its two borders. 



DISSECTION OF AETICULATIOKS OF PELVIS. 535 



Dissection of the Aeticulations of the Pelvis. 

Tlie pelvis is articulated above with the vertebral column, 
and below with the femora. The degree of mobility allowed 
by these articulations is very different. Between the bones 
of the pelvis, except between the sacrum and coccyx, no mo- 
tion is required, unless it be in the female during parturition. 

The sacro-vertehral articulation is formed by the last lumbar 
vertebra and the sacrum. With the exception of the sacro- 
vertebral and ilio-vertebral ligaments, the connecting media 
are the same as between the different vertebrse. 

The Sacro-Yeetebeal Ligament, Fig. 220 (2), is of a 
triangular shape, and extends from the transverse process of 
the last lumbar vertebra to the upper or horizontal surface 
of the corresponding ala of the sacrum. Its fibres spread 
out towards the sacro-iliac symphysis. 

The Ilio-Yeetebeal Ligament, Fig. 220 (3), of a trian- 
gular form, extends from the transverse processes of the last 
two lumbar vertebrse to the crest of the ilium. It fills up a 
notch that would otherwise exist at this point. Sometimes 
there are two of these ligaments on the same side. 

The sacro-coccygeal articulation presents two ligaments, one 
before and the other behind; and a thin layer of cartilage 
placed between the two bones, where a small synovial sac is 
sometimes met with, especially in the female. 

The Anteetoe Saceo-Coccygeal Ligament is composed 
of irregular fibres, and is much thinner than the posterior. 

The PosTEEiOE Saceo-Coccygeal Ligament, Fig. 232 
(1 0), is quite a thick, strong ligament. It extends downwards 
over the different pieces of the coccyx, closes in the lower 
extremity of the sacral canal, and protects the last nervous 
cords of the medulla spinalis. 

The mobility of this articulation is said to be greater in 
the female than in the male; and in women who have borne 
children, its mobility is preserved for a much longer period 
of life than in those who have not. If it were not for the 
sacro-sciatic ligaments, the motion between the sacrum and 
coccyx would be greater than it is. 

The number of coccygeal articulations vary greatly in 



536 THE LOWER EXTREMITY. ^ 

different subjects, and at different periods of life. In the 
young subject, a thin fibro-cartilage is found between the 




A Posterior View op the Ligaments of the Pelvis. — 1. Base of the Sacrum. 
2. The coccyx. 3, 3. The crests of the ilia. 4, 4. The tuberosities of the ischia. 
5, 5. The great sciatic notches. 6. The small sciatic notch. 7. The femur. 8, 8. 
The posterior saero-iliac ligaments. 9. An oblique fasciculus. 10. The posterior 
sacro-coccygeal ligament. 11. The obturator ligament. 12. The sub-pubic fora- 
men. 13, 13. The origin of the great sacro-sciatic ligament. 14. Its insertion. 
15. The origin of the small sacro-sciatic ligament. 16, Its insertion. 

bones, while in the old the joints are most commonly oblite- 
rated. The sacrum and coccyx are also in the old generally 
united by osseous substance. 

The sacro-iliac articulation is formed by the sacrum and 
ilium. The articular surfaces, from their shape, have been 
called the auricular facets. The connecting media consist of 
anterior and posterior fibres, and an intermediate layer of 
cartilage^ which adheres very closely to the bones. 

The Anterior Sacro-Iliac Ligament, Fig. 233 (7), is 
composed of a thin layer of fibres, extending transversely 
from one bone to the other ; they are scarcely raised above 
the contiguous smooth surfaces. 

The Posterior Sacro-Iliac Ligament, Fig. 232 (s), con- 
sists of several fasciculi, which extend from a rough surface 
behind the auricular facet of one bone to a corresponding sur- 
face on the other. Some of the fibres are oblique, and others 



DISSECTION OF ARTICULATIONS OF PELVIS. 537 

are nearly transverse. One or. two of the ohlique fasciculi^ 
Fig. 232 (9), have been described as distinct ligaments. The 
ligament is situated deeply in the groove formed between the 
sacrum and ilium; it requires considerable time and patience 
to make a satisfactory exposition of all its fibres or fasciculi. 
A synovial membrane is sometimes found in this articulation, 
especially in the female, while a soft yellowish substance. is 
sometimes met within it in the male. As it is occasionally 
desirable to disarticulate the os innominatum, as in making 
a dissection of the pelvic viscera, the student shonld be care- 
ful to ascertain the exact position of the symphysis, in front, 
and divide all the fibres of the anterior ligament, when a 
small scalpel can be carried through the cartilage which 
connects the two bones forming the joint. 

The two following ligaments connect the sacrum and coc- 
cyx to the ischium. They enter so largely into the formation 
of the pelvic parietes, and sustain such important relations 
to various parts, that the student cannot neglect to obtain a 
thorough knowledge of them without doing great injustice 
to himself. They should be carefully studied before he 
attempts to make a dissection of the pelvis or the pelvic 
viscera. Their value in the mechanism of the pelvis will be 
observed the moment that he contrasts an articulated pelvis, 
composed simply of the bones, with one prepared with these 
ligaments cleaned and retained in situ. 

The Posterior or Great Sacro-Sciatic Ligament, Fig. 
233 (4), is of a somewhat triangular shape, with the hase 
attached to the posterior inferior spinous process of the ilium 
and to the border of the sacrum and coccyx, and the apex to 
the inner edge of the tuberosity of the ischium and to the 
ramus of the same bone. The obturator fascia is connected 
to the anterior or falciform portion of this ligament, which 
projects a little into the perineum, and serves to protect the 
internal pudic vessels. The posterior surface of this liga- 
ment is occupied by the origin of a part of the gluteus maxi- 
mus muscle, while the anterior surfiice is partly free, looking 
into the pelvic cavity, and partly in apposition with the short 
ligament. It is perforated by small foramina for the trans- 
mission of vessels. 

The Anterior or Small Sacro-Sciatic Ligament, Fig. 
233 (5), is attached behind to the side of the sacrum and 



538 



THE LOWER EXTREMITY. 



Fig. 233. 




coccyx, and anteriorly to tlie spine of the iscbiam. Its form 
is triangular, and its direction is nearly transverse. Pos- 
teriorly, it is covered principally 
by the great ligament, with which 
its fibres are more or less inter- 
mingled, especially at its base 
or near the sacrum. Anteriorly, 
it is in apposition with the coc- 
cygeus muscle. 

The great and small sacro- 
sciatic notches, which exist in 
the osseous pelvis, are by these 
two ligaments converted into 
the great and smo.ll sacro- sciatic 
foramina^ Fig. 233 (1,2). As the 
spine of the ischium separates 
the two notches, so the small 
sacro- sciatic ligament separates 
the two foramina. The contents 
of these foramina require par- 
ticular notice in the dissection 
of the parts inside of the pelvis 
and in the gluteal region. 

The articulation formed by 
the bodies of the pubic bones is designated the symphysis 
py.his^ Fig. 233 (e). The space between these bones is of a 
cuneiform shape, the base looking forwards and downwards, 
and the thin edge backwards and upwards. This space is 
filled with fibro-cartilage, including sometimes an imperfect 
synovial sac, especially in the female. The fibro-cartilage is 
arranged in concentric layers of an elongated oval form; 
short fibres penetrate and connect them together, except in 
the centre and posteriorly, where a soft pulpy substance is 
found, or the synovial sac when present. As the iamin^B 
just fill the circumference of the space between the bones, 
they are thicker or more numerous in front than behind, 
where they project so as to form a vertical ridge; some of 
them may be entirely deficient behind. 

Surrounding this intermediate structure, ligamentous fibres 
extend from one bone to the other. They are named accord- 
ing to their location. Thus, we have quite a thick, strong 
fasciculus of fibres above, passing from one bone to the other 
and continuing some distance on their upper borders ; this 



A Section op the Pelvis^ show- 
ing THE Ligaments and Sacro- 
SciATic Foramina on the Left in- 
ner side, viz: 1. Great saero-sciatic 
foramen. 2. Small sacro-sciatic fora- 
men. 3. Sacro-coccygean ligament. 
4. Great sacro-sciatic. 5. Small sa- 
cro-sciatic. 6. Symphysis pubis. 7. 
Anterior sacro-iliac ligament. 10. 
Obturator. 



DISSECTION OF BACK OF THIGH AND THE HAM. 539 

is named the superior pubic ligament. Behind, there are fibres 
which connect the two bones together ; they do not form, 
however, so thick a layer as the upper and anterior ones do ; 
they constitute \hQ posterior pubic ligament. Anteriorly, there 
is also the same arrangement of fibres, forming the anterior 
pubic ligament. Below, the fibres interlace, and extend down- 
wards on the rami of the pubes, and form the sub-pubic 
ligament^ which is of a triangular shape. This ligament 
rounds off the angle formed by the rami of the pubic bones, 
and forms the summit of the pubic arch. The symphysis 
pubis is supposed by some to allow of a slight degree of 
mobility in parturition. If motion takes place at all, it must 
be so little as to produce scarcely any appreciable effect in 
increasing the diameters of the pelvis. 

The Obturator Ligament or Membrane, Fig. 233 (i o), 
occupies the obturator foramen. It presents an opening 
called the sub-puUc foramen, Fig. 232 (12), in the upper part, 
corresponding to the sub-pubic groove in the horizontal 
ramus of the os pubis, for the transmission of the obturator 
nerve and vessels. Its surfaces are occupied by the origins 
of the obturator muscles. This fibrous membrane is a sub- 
stitute for osseous structure in the parietes of the pelvis, 
which are probably rather strengthened than weakened by 
it; it may also yield somewhat in parturition, and thus facili- 
tate the passage of the head of the child through the pelvis. 
Another advantage said to be derived from it, is that it is 
lighter than bone would be; the difference, however, between 
its weight and that of a thin lamella of bone could make no 
manifest difference. 

Pouparis and Gimbernais ligaments, Fig. 220 (e, 7), are 
formed by the lower border of the tendon of the external 
oblique muscle, with the addition of some fibres which arise 
from the anterior superior spinous process of the ilium ; they 
are noticed in the dissection both of that muscle and of the 
femoral region. 

Sect. III. — Dissection of the Back of the Thigh, and 

OF THE llXM. 

The back part of the tliigli and the popliteal space should 
be examined at the same time, commencing the dissection 
above, and extending it down as far as the back of the 



540 



THE LOWER EXTREMITY. 



Fig. 234. 



A 



leg. Witli a little attention, the student will be able to 
ascertain the best position in which to place the limb as he 
proceeds with the dissection. To expose the long muscles 
on the back of the thigh, the leg should be extended on the 
thigh, and the thigh flexed on the pelvis. To remove the 
skin, an incision may be made through it in the median line 
of the limb, beginning at the gluteal region and terminating 
about three or four inches below the knee-joint; but if the 
anterior part of the thigh has already been dissected, the in- 
tegument may be removed, by simply reflecting it either from 
the inner or the outer part of the limb. 

The superficial fascia in these regions is merely a continua- 
tion of the superficial fascia from the fore 
part of the thigh and the pelvis. There are 
no arteries that require any particular no- 
tice in this fascia; and the only vein of suf- 
ficient importance, and which was not seen 
in the dissection of the anterior part of the 
thigh, to be particularly noticed, is the ex- 
ternal saphenous. 

The external or short saphenous vein is a 
continuation of the external dorsal vein 
of the foot. It will be found, in this dissec- 
tion, extending up the back part of the leg 
in the median line, and entermg the pop- 
liteal space to open into the popliteal vein. 
Sometimes quite a large venous trunk is 
found going from this vein to the upper 
part of the thigh, where it unites with a 
branch of the internal saphenous, or of the 
deep femoral vein. 

The cutaneous nerves^ Fig. 234 (2, 2), on the 
back part of the thigh and in the ham are 
'^'^1 1 derived, on the inner side, from the internal 
cutaneous, and from the internal saphenous, 
or the obturator nerve ; on the outer side, 
from the external cutaneous ; a.nd in the mid- 
dle, from the posterior femoral cutaneous. 

Plan of the Cutaneous Nerves on the Posterior Aspect of the Left Leg. — 
1. Inner division of the internal cutaneous nerve. 2, 2. Branches of the long or 
internal saphenous. 3. A branch of the posterior femoral cutaneous ; the offset 
above it in a direct line is a branch of the same nerve. 4, 6. Short or external sa- 
phenous nerve. 5, 7. Peroneal cutaneous nerve. 



DISSECTION OF BACK OF THIGH AND THE HAM. 541 



The one derived from the small sciatic, and descending on 
the back of the thigh, is called tYiQ posterior femoral cutaneous 
branchy Fig. 235 (2,3). It gives off external and internal 
filaments in its course down the thigh. One of its terminal 
branches becomes subcutaneons in the popliteal space, and 
can be traced some distance on the back of the leg. The 
other terminal branch does not perforate the deep fascia until 
it reaches the back of the leg, where it usually ends by anas- 
tomosing with the external saphenous nerve. The super- 
ficial fascia may now be removed, when 
the fascia lata will be exposed. This is Fig. 235. 

continuous above with the gluteal fascia 
or aponeurosis, on each side with the 
fascia lata, where it joins the internal and 
external intermuscular septa, and below 
with the deep fascia of the leg. It forms 
a sheath for the long muscles on the back 
of the thigh, and stretches across the pop- 
liteal space, so as to protect the vessels 
and nerves in that region ; near the knee 
it is strengthened by fibres derived from 
the tendon of the biceps flexor and the 
vasti muscles. 

The fascia lata should now be divided 
along the median line, and reflected to 
each, side, so as to expose the parts be- 
neath it. Having removed the fascia lata, 
the small or lesser sciatic nerve should be 
traced down the thigh to the back part of 
the leg. The following muscles may be 
examined next, taking care not to destroy 
the great sciatic nerve. 

The Biceps Flexor Cruris, Fig. 215 
(4, 5), as its name indicates, arises by two 
heads. The long head arises tendinous, in 
common with the semi-tendinosus, from 
the posterior and upper part of the tuber- 
osity of the ischium, from the lower part 

A View of tiir Internal Poptjteat. Nerve ani> some of its Branches on the 
Right Leg. — 1. The internal popliteal nerve. 2, 3. The terminations of the ramus 
feinoralis cutaneus posterior. 4, 5. The internal saphenous nerve. 6, 6. The ex- 
ternal saphenous or communicans tibialis. 

46 



/y 



542 THE LOWER EXTREMITY. 

of whicli it is separated by a bursa ; tbe short head arises^ 
muscular, from the linea aspera and the external intermus- 
cular septum, commencing where the insertion of the gluteus 
maximus ends, and extending down near to the condyle. 
The long head and the semi-tendinosus separate from each 
other about three inches below their common origin. The 
two heads unite to form a round tendon, which passes down- 
wards and outwards, and is inserted by two fasciculi into the 
head of the fibula. The long external lateral ligament of 
the knee-joint is placed between these fasciculi; some fibres 
extend from one of these fasciculi to the fascia of the leg, and 
some from the other fasciculus to the head of the tibia. 

The Semi-Texdixosus, Fig. 215 (e), arises, tendinous and 
muscular, from the tuberosity of the ischium in common with 
the long head of the biceps, passes at first directly down- 
wards, and then inwards, becoming tendinous a short dis- 
tance below the middle of the thigh. Its tendon, small and 
slender, passes around the inner side of the knee-joint, then 
forwards, and is inserted into the tubercle of the tibia. Its 
tendon, joined with those of the sartorius, gracilis, and semi- 
membranosus, form what has been called the gooseys foot. 
The appropriateness of the name of this muscle will be seen 
when the relative length of its tendon is noticed. 

The SEin-MEMBRANOSUS, Fig. 215 (7, 7), arises from the 
posterior part of the tuberosity of the ischium, in front of the 
biceps flexor and semi-tendinosus and behind the quadratus 
femoris, and passes downwards and inwards to the inner and 
posterior part of the knee-joint, where its tendon divides 
into three processes, one of which is inserted into the apo- 
neurosis that covers the popliteal muscle; another, pass- 
ing under the internal lateral ligament, is inserted into the 
inner tuberosity of the tibia; the third one forms a part of 
the posterior ligament of the knee-joint or the ligament of 
Winslow; this part of it is inserted into the external con- 
dyle of the femur. The upper tendon is quite long, flat, and 
aponeurotic; the lower part of it consists of tw^o laminae, from 
the opposing surfaces of which fibres arise to form the upper 
part of the belly of the muscle. The lower tendon is round 
and very short. By this arrangement of the muscular bellies 
of the semi-tendinosus and semi-membranosus, the symmetry 
of the back part of the thigh is preserved, the belly of each 



DISSECTION OF BACK OP THIGH AND THE HAM. 543 

corresponding to the long tendon of the other. These two 
muscles form the inner hamstring^ although the sartorius and 
gracilis are sometimes spoken of as hamstring muscles. The 
biceps flexor forms the outer hamstring. The tendons of 
these muscles should be studied with reference to the opera- 
tion of tenotomy. They can be distinctly felt in the living 
subject, becoming very prominent when the leg is partly 
flexed on the thigh. 

The actions of the three muscles just described are the same 
as far as flexing the leg on the thigh, or keeping the axis of 
the pelvis parallel with that of the lower limb, as when 
standing. When the leg is partly flexed, they can rotate it 
very little, the biceps outwards, and the other two inwards. 
Through the connection of the semi-membranosus with the 
posterior ligament of the knee-joint, it can draw the syno- 
vial membrane backwards. 

The arteries involved in dissecting the preceding muscles 
are principally branches of the profunda and popliteal. Those 
derived from the profunda are the internal circumflex and the 
perforating branches. The internal circumflex^ Fig. 217 (s), 
reaches the back of the thigh by passing, first, between the 
pectineus and the capsular ligament of the hip-joint, to which 
it sends a branch through the notch at the bottom of the 
acetabulum, and then between the quadratus femoris and the 
adductor magnus. It divides into ascending and descending 
tranches; the latter of which are distributed in part to the 
muscles just examined, and to the integument in this region; 
the former go to the muscles on the back and lower part of 
the pelvis, the gluteus maximus and the small rotator mus- 
cles. This artery anastomoses with the obturator, sciatic, 
and several others. 

The perforating branches, Fig. 217 (i i, i 2, i s), vary in num- 
ber; being sometimes two and sometimes three, besides the 
terminal branch of the profunda. The first one perforates the 
adductor muscles a short distance below the trochanter minor, 
and, passing backwards partly around the shaft of the femur, 
divides into ascending and descending branches; some of 
which terminate in tlie muscles of this region, and some go 
to supply the integument. It anastomoses above Avith the 
internal circumflex, externally with the external circumflex, 
and below witli the next perforating branch. It usually sup- 
plies the femur with its nutritious artery. The other per- 



544 THE LOWER EXTREMITY. 

forating branches, including the terminal branch, require no 
particular description. They perforate the adductor mnscles, 
and are distributed in the same manner as the first, of which 
they are sometimes branches, instead of arising directly from 
the profunda. The branches of the popliteal, as well as the 
popliteal itself, will be noticed at another time. 

The GrREAT Sciatic Nerve, Fig. 192 (7), has been noticed 
in the dissection of the parts within the pelvis, and atlso in 
the gluteal region. It enters the back part of the thigh, be- 
neath the lower border of the gluteus maximus, and resting 
on the qnadratus femoris, being in a line midway between 
the tuberosity of the ischium and the trochanter major. For 
a short distance below the gluteus maximus it is subapo- 
neurotic, having no muscle between it and the integument. 
It then passes under the long head of the biceps, and con- 
tinues dowm the thigh, being inclined a little outwards, to the 
upper part of the popliteal space, where it divides into the 
internal and external ])o]^liteal nerves. This division sometimes 
takes place before it leaves the pelvis; or it may occur at any 
point after it leaves the pelvis. When it divides in the pelvis, 
the upper division usually perforates the pyriformis muscle. 
It is surrounded by a large quantity of areolar tissue, and of 
adipose substance, if the subject be fat. Its position should 
be noticed with reference to acupuncture, or injuries of it, 
from whatever cause. It will be observed that it can be 
reached below the biceps without passing through any muscle, 
and also between that muscle and the gluteus maximus. 

Having examined the main trunk, it should now be traced 
from above downwards, to find the branches given ofl' from 
it. They consist of muscular and articular branches ; the latter 
go to the knee-joint; two branches are distributed to the 
semi-membranosus ; one to the semi-tendinosus ; one to the 
long head, and one to the short head, of the biceps; and one 
to the adductor magnus. These nerves, except the one to 
the short head of the biceps, usually arise just as the sciatic 
nerve enters the back of the thigh, sometimes coming off 
from it by a single trunk, and afterwards dividing. The 
adductor magnus is supplied principally by branches which 
come from the obturator nerve ; the one that comes from the 
sciatic penetrates the inner border of the muscle some dis- 
tance below its origin. The branch which goes to the short 



DISSECTION OF BACK OF THIGH AND THE HAM. 545 



head of the biceps sometimes arises with the preceding, and 
sometimes by itself, lower down. Those that go to the other 
three muscles, generally run some distance before penetrat- 
ing them, which they do on their anterior surfaces. 

The posterior surface of the adductor magnus, Fig. 216 (is), 
should be noticed so that a clearer idea of the muscle can be 
obtained than could be, by simply examining it when the an- 
terior part of the thigh was dissected. Its relations to so many 
parts renders a knowledge of it very im- 
portant to the student. The obturator ex- Fig- 236. 
ternus should also be examined now more 
thoroughly than could be done before. 

The popliteal sjMce, and its houndanes, 
Fig. 236 (s), should next be examined. It 
is somewhat diamond-shaped, the broadest 
part corresponding to the knee-joint. It is 
covered in by the integument and a strong 
aponeurotic fascia, which is continued, as 
was noticed before, from the fascia lata on 
the back of the thigh. This fascia serves to 
protect the parts in this space, and, in case 
of aneurism of the popliteal artery, or of 
an accumulation of pus beneath it, offers 
strong resistance, which renders such cases 
very painful. It is connected laterally, to 
the condyles of the femur and to the tendons 
of the muscles. The upper part of the space 
is bounded, on the outer side, by the biceps 
flexor muscle, and on the inner side, by the 
semi-tendinosus, semi-membranosus, and 
the adductor maguus. The lower part has, 
on the outer side, the external head of the ^4', 

gastrocnemius and the plantar is, and on 
the inner side, the internal head of the gas- 
trocnemius. The anterior boundary or the 
floor of tliis space, is formed by the pop- 

TiiE Superficial Muscles of the Posterior Aspect of the Leg. — 1. The 
biceps muscle forming the outer hamstrinc:. 2. The tondons forming the inner 
hamstring. 3. The popliteal space. 4, 4. The gastrocnemius muscle, b, 5. The 
soleus. 6. The tendo-Achillis. 7. The posterior tuberosity of the os calcis. S. 
The tendons of the pcronens longus and brevis muscles passing behind the outer 
ankle. 9. The tendons of the tibialis posticus and tlexor longus digitorum passing 
into the foot behind the inner ankle. 

46-^- 



546 



THE LOTTEE EXTEEAIITY. 



liteal fossa of the femur, the posterior part of the knee-joint, 
and the popliteus muscle, or the aponeurosis which covers it. 
The popliteal region generally contains a considerable 
quantity of areolar tissue and adipose substance, ^hich ren- 
ders the dissection of its contents diflS.cult, 
requiring time and patience to do it in 
a proper manner. The vessels consist of 
the popliteal artery and its branches, 
and of the accompanying veins. The 
nerves are the internal and external 
popliteal, and their branches. 

The Popliteal Yeix, Fig. 240 (i), is 
placed between the artery and the inte- 
gument, so that it will be found in the 
dissection before the artery. The 'pos- 
terior or external saphetwus vein^ Fig. 
240 (t), will also be observed entering 
the popliteal space above the joint, and 
usually sending off a branch which 
passes upwards, and anastomoses with 
the inferior perforating branch. 

The large nerves are more superficial, 
and are situated, except at the lower 
part of the popliteal space, nearer to its 
outer border than the artery or vein, 
and consequently should be looked for 
in the dissection before those vessels. 

The IxTEEXAL Popliteal Xeeve, Fig. 
237 (i, 2), is the largest of the two divi- 
sions of the great sciatic, of which it 
seems to be a continuation ; it is nearly 
twice the size of the external popliteal 
nerve. The biceps flexor muscle partly 
covers it above the knee-joint. It gra- 
dually approaches the artery, and finally 
crosses it and the vein. It takes the 
name of posterior tibial nerve in the 
leg. It gives off several branches, some 
of which are muscular^ one cutaneous^ 
and others articular. 
The rrtuscular hranclies arise from it behind the ioint, and 




i 



'3 



> 



A VlZ^- OF THE INTER- 
NAL Popliteal axd Pos- 
terior Tibial Xerves ix 

THE HaIT and the BACK 

OF THE Leg. — 1, 2, indi- 
cate the course of them; 
the upper part of the ex- 
ternal popliteal nerve is 
seen to the right. 



DISSECTION OF BACK OF THIGH AKD THE HAM. 547 

are distributed to tlie muscles in the upper and back part of 
the leg. Two of them, quite large, and sometimes arising 
by a common trunk, go to the heads of the gastrocnemius. 
They ramify on the anterior surface of each head before 
penetrating its substance. A smaller one goes to the plan- 
taris, entering its inner and anterior surface ; sometimes this 
is a branch of the preceding nerve. Another branch passes 
downwards, and gets between the soleus and gastrocnemius 
muscles, and, after ramifying on the posterior surface of the 
soleus, penetrates its substance. The last muscular branch 
goes to the popliteus ; after passing down to the lower bor- 
der of the muscle, turns around it and passing upwards, rami- 
fies on its anterior or deep surface. It sends an articular 
branch to the tibio-fibular articulation. 

The cutaneous branch is known by several names, as the 
tibial^ shorty or external saphenous^ the posterior cutaneous nerve 
of the leg, and the commumcans tibialis^ Fig. 235 (e, e). It 
usually arises opposite the articulation, and passing doAvn- 
wards first between the heads of the gastrocnemius, and then 
on its posterior surface in a small fibrous canal, perforates 
the deep fascia near the junction of the upper with the 
middle third of the leg ; sometimes it continues lower down 
before it becomes subcutaneous. It is joined by the com- 
municans peronei nerve, a branch of the external popli- 
teal. The point of union varies greatly, occurring sometimes 
in the upper part of the leg, and then again not until it has 
nearly reached the foot. This nerve will be referred to 
again in the dissection of the back of the leg and the dorsum 
of the foot, on the outer part of which it terminates. 

The articular branches are three in number, and correspond 
to the internal and middle articular branches of the popliteal 
artery, except there is but one superior internal artictdar nerve ^ 
whereas there are two of these arteries; and sometimes this 
branch, always small, is absent. When present, it passes in 
front of the popliteal vessels to reach the artery, which it 
accompanies in its distribution to the joint. The inferior in- 
ternal articular branch arises above the joint, and, passing 
dowuAvards, at first on the outer side of the vessels, then in 
front of them, joins the corresponding articular artery, which 
it accompanies in the rest of its course. It is larger than 
either of the other articular branches for the knee-joint. The 
middle articular branch arises opposite the articulation, and 



548 THE LOWER EXTREMITY. 

proceeds directly to tlie interior of tlie joint, perforating the 
posterior ligament. 

Tlie External Popliteal or Peroneal Nerye, Fig. 
237, passes downwards along the biceps flexor muscle, in the 
outer part of the popliteal space, to the point opposite the 
tibio-peroneal articulation, when it turns outwards, and pene- 
trates the peroneus longus muscle just below the head of the 
fibula. While in this muscle, or placed between it and the 
cervix of the fibula, it divides into its terminal branches, 
the anterior tibial and the musculo -cutaneous, Fig. 248. These 
will be described in the dissection of the anterior part 
of the leg, and the dorsum of the foot. The peroneal nerve 
is rather more superficial in its course than the internal pop- 
liteal. It passes over the external condyle of the femur, 
and the external head of the gastrocnemius. It gives off 
articular and cutaneous branches ; of the latter, the communi- 
cans peronei or the peroneal saphenous, is the largest. This 
visually arises a little above the knee-joint, and passing 
downwards on the inner side of the peroneal nerve, gets be- 
tween the gastrocnemius and the deep fascia, which it perfo- 
rates to unite with the communicans poplitei. Its junction 
with the communicans poplitei is not constant, and varies 
very much as to the point at which it takes place. It gives 
off several small cutaneous branches in its course down the 
leg. The other cutaneous branch, the peroneal cutaneous, 
given off by the peroneal nerve, descends behind the exter- 
nal condyle, and passing down on the outside of the leg, 
gives off branches which ascend and descend to supply the 
integument on that part of the leg. The articular branches 
correspond to the superior and inferior external articular 
branches of the popliteal artery. The superior external Ojrti- 
cular branch sometimes arises from the sciatic nerve. It 
passes downwards in front of the sciatic nerve, when it 
arises from that nerve, and along the biceps flexor muscle to 
near the external condyle, then turns outwards above it to be 
distributed to the joint in company with the corresponding 
artery. The inferior external articular nerve usually has nearly 
the same origin as the preceding nerve. It passes down- 
wards in the outer part of the popliteal space to a point just 
below the external condyle, and then turns outwards to be 



DISSECTION OF BACK OF THIGH AND THE HAM. 549 



distributed to the joint in company with, the inferior external 
articular artery. 

The Popliteal Aeteey, Fig. 238 (i), is a continuation of 
the femoral. It commences at the lower end of the canal 
formed by the tendons of the adductores longus and magnus, 
and passes downwards and outwards, first over the femur, 
then the posterior ligament of the 
joint, and lastly the aponeurosis, which 
covers the popliteal muscle, at the 
lower border of which, it divides into 
the posterior tibial and peroneal or 
fibular. At first, it is to the inner 
side of the median line of the limb, 
but gets into it as it descends behind 
the joint. The popliteal vein, Fig. 
240 (5), lies behind and a little to the 
outer side of it above the joint, but 
directly behind it in the rest of its 
course. The coats of this vein are 
Yerj thick, so that when cut it some- 
times gapes, and might then be mis- 
taken for the artery. It also adheres 
very closely to the artery, which 
should be borne in mind, whenever 
it is necessary to place a ligature on 
the latter. The lower part of the 
artery is partly covered by the heads 
of the gastrocnemius and the plant- 
aris; the popliteal nerve also crosses 
this part of it from the outer to the 
inner side. It has on the sides of it 
the different parts which form the 
boundaries of the popliteal space, 
which are specified above. The relations of the popliteal 
artery to the knee-joint are interesting, and should be care- 
fully observed. When one hmb is placed across the other, as 
in sitting, the pulsations of the artery are distinctly seen in 
the movements of the foot, so that the beats of the heart can 
be counted as accurately, by observing the movements of the 
foot with the legs crossed, as by placing the fingers on the 
radial artery in the wrist. There are etght branches given 




IN 



A View of the Arteries 
THE Popliteal Space, 
Right Leg. — 1. Popliteal 
artery. 2. Internal gastroc- 
nemial artery. 3. External 
o;nstrocnemial arter}'. 4, 5. 
Division of these arteries iu 
the substance of the muscle. 



550 THE LOWER EXTREMITY. 

off from the popliteal artery, whicli require to be noticed. 
Six of these are articular branches, and two are muscular. 

The superior internal articular arteries^ consist of two. One 
of these is sometimes called the great anastomotic artery^ Fig. 
213 (20, 21), of the knee. It may arise from the femoral 
artery as it is passing through the tendinous sheath to be- 
come the popliteal; or it may have its origin still higher up. 
After perforating the adductor magnus, it divides into several 
branches. One of these passes downwards behind the sar- 
torius muscle, in company with the internal saphenous nerve; 
another one passes dowuAvards through the substance of the 
vastus internus muscle, and, reaching the inner border of the 
tendon of the quadriceps extensor muscle, just above the pa- 
tella, where it becomes subcutaneous, and crossing transversely 
to the outer side, along the upper border of the patella, it 
anastomoses with the superior external articular branch. It 
sends branches to the anterior surface of the patella. One 
or two branches are distributed principally to the periosteum 
on the inner and anterior surface of the femur. One of these 
sometimes takes the place of the next artery to be de- 
scribed, or terminates by anastomosing with it. 

The lower superior internal articular artery^ Fig. 239 (4), 
arises just above the internal condyle, passes horizontally 
inwards and around the condyle, to gain its anterior surface. 
It sends branches to the patella and to "the synovial mem- 
brane, and other branches to the integument, and to anasto- 
mose with the preceding branch and one or two of the other 
articular branches. 

The superior external articular artery^ Fig. 239 (5), arises just 
above the external condyle, and, passing under the biceps 
flexor muscle, divides into several branches; some of which 
are muscular, and others are periosteal. The former are 
ascending branches, and go to the biceps and the quadriceps 
extensor muscles. The latter are found ramifying on the 
condyle and the anterior surface of the lower part of the 
femur, and also on the outer part of the patella. They also 
anastomose freely with the other articular branches.- 

The inferior external articular artery^ Fig. 239 (s), arises oppo- 
site the articulation, and passing horizontally outwards in a 
line corresponding to the joint, and beneath the tendon of 
the biceps and the external lateral ligaments, divides into an 
ascending, a transverse, and a descending branch. The first 



DISSECTION OF BACK OF THIGH AND THE HAM. 551 



passes upwards along tlie outer border of the patella, and 
anastomoses with the superior external articular artery. The 
second, passing transversely below the 
patella and between the ligamentum Fig° 239. 

patellae and the joint, anastomoses with 
the inferior internal articular artery; 
it also sends small branches to the fat 
and areolar tissue beneath the liga- 
mentum patellae. The last one anasto- 
moses with the anterior recurrent tibial, 
a branch of the anterior tibial artery. 

The inferior internal articular artery^ 
Fig. 239 (7), arises opposite to the pre- 
ceding artery, and passing downwards 
and inwards around the internal tube- 
rosity of the head of the tibia, and be- 
neath the tendons of the muscles which 
form the inner hamstring, and the 
internal lateral ligament of the knee- 
joint, it turns upwards towards the 
patella. It anastomoses with the pre- 
ceding artery beneath the ligamentum 
patellse, and also with the superior 
internal articular arteries. 

The middle articular artery^ or the 
azygos artery^ Fig. 239 (e), arises from 
the forepart of the popliteal artery, 
and passes directly through the pos- 
terior ligament, to be distributed to the 
synovial membrane, the areolar tissue, 
and the crucial ligaments within the 
knee-joint; some of its branches pene- 
trate the lower extremity of the femur. 

A View of the Arteries on the Back of the Rioht Leg. The Muscles hate 

BEEN removed SO AS TO DISPLAY THE VESSELS IN THEIR WHOLE LENGTH. — 1. The 

popliteal artery, cut off so as to show the articular arteries. 2. Lower end of tho 
same artery on the popliteus muscle. 3. Point of bifurcation into the posterior 
tibial and peroneal. 4. Lower superior internal articular artery. 5. Superior ex- 
ternal articular artery. 0. Middle articular artery. 7. Inferior internal articular 
artery. 8. Inferior external articular artery. 0. .Branch to the head of the sulcus 
muscle. 10. Origin of tho anterior tibial artery. 11. Origin of the posterior tibial 
artery. 12. Point where it passes behind tho internal annular ligament to become 
the plantar. 13, It, 15. Muscular branches. 16. Origin of the peroneal artery. 
17, 17. Muscular branches. 18, 18. Anastomosis of the posterior tibial and pero- 
neal arteries near the heel. li). Muscular branch from the anterior tibial. 




552 THE LOWEE EXTREMITY. 

Instead of one middle artery, there may be several smaller 
ones going to supply tlie same parts. Like those which have 
been described above, it may take its origin from some one of 
the other articnlar arteries ; all the arteries around the knee- 
joint vary more or less in their origin, and also in their size. 
The patella is the centre of their anastomotic connections. 

The gastrocnemial arteries^ Fig. 238 (2, 3), arise from the 
back of the popliteal artery, nearly opposite the articulation, 
and passing downwards are distributed, one to each of the 
heads of the gastrocnemius. They are usually larger than the 
articular branches. They correspond to muscular branches 
given off from the popliteal artery, above the knee-joint, to 
be distributed to the muscles in the lower part of the thigh. 



Sect. IY. — Dissection of the Posterior and the Inner 

PART OF THE LeO. 

To dissect the posterior part of the leg, the integument 
may be removed by making an incision from the popliteal 
space along the median line to the heel, and thence along 
both the inner and outer borders of the plantar surface of the 
foot to a point on each side below the malleolus. From this 
incision the skin can be reflected externally and internally 
sufficiently to expose all the parts in this region. The foot 
should be flexed on the leg so as to make the fascia, as well 
as the muscles to be dissected, tense. Although it is conve- 
nient to describe, at this time, the parts which correspond to 
the subcutaneous surface of the tibia, it is not necessary that 
the integument which covers this surface should be removed 
in connection with that on the back of the leg. It is better 
that the student should dissect specially for the internal sa- 
phenous vein and nei've^ as there is nothing else of any im- 
portance on the inner part of the leg. The vein, if injected, 
or filled with blood, is easily found and traced; but it is 
much more difficult to find the nerve, unless it was preserved 
when the dissection of the anterior part of the thigh was 
made. To dissect them on the leg, it is immaterial whether 
the subject be placed on the back or on the face; if on the 
back, the integument can be reflected from behind forwards, 
and the dissection can be made in connection with the back 
of the lesf. 



POSTERIOE AND INNER PART OF THE LEG. 553 

Having reflected the integument from the incision made 
in the median line to a line corresponding to the fibula and 
external malleolus on the outer side, and to the inner angle 
of the tibia and internal malleolus on the inner side, the cuta- 
neous vessels and nerves should, be examined. If it be de- 
cided to dissect the internal saphenous nerve and vein in 
connection with the back of the leg, then the internal flap 
must be raised as far as the anterior angle or spine of the 
tibia. Special care is requisite in raising the integument 
that the superficial fascia be left in order that the cutaneous 
vessels and nerves may not be injured or destroyed before 
they have been dissected. 

There are no arteries in the superficial fascia that require 
particular notice. 

The veins to be examined in the superficial fascia are the 
two saphenous, external and internal. The latter was dis- 
sected in the upper part of its course in connection with the 
thigh, and the former, with the popliteal space. They both 
commence on the dorsum of the foot, and are subcutaneous 
to within a very short distance of their termination, the one 
in the femoral, and the other in the popliteal vein. They 
communicate freely with each other on the leg, and sometimes 
the external joins the internal instead of the popliteal. They 
contain very few valves, which ma}^ contribute to the forma- 
tion of varix, and also tend to prevent the obliteration of 
the veins, as they can, in the absence of valves, more readily 
empty themselves by means of collateral branches ; the in- 
ternal has from two or three to six valves^ and the external 
only two. 

The Internal Saphenous Vein, Fig. 208, arises by the 
internal dorsal vein of the foot, passes backwards and upwards 
on the inner part of the dorsum, and in front of the ankle- 
joint to the anterior part of the internal malleolus, and thence 
along the inner angle of the tibia to the internal and poste- 
rior part of the knee-joint. In this part of its course it re- 
ceives branches from both sides of it. In the foot it commu- 
nicates with the deep plantar vein, and receives the superficial 
veins of the inner part of the plantar portion of the foot, 
including the internal calcaneal veins. Sometimes the last- 
named veins form a trnnk which passes upwards behind the 
internal malleolus, and there unites with the saphenous. 
47 



654 THE LOWER EXTREMITY. 

From the knee to the saphenous opening in the fascia lata, 
the internal saphenous was described in connection with the 
anterior part of the thigh. Below the knee it is accompanied 
by one of the terminal divisions of the internal saphenous 
nerve. This is the longest vein in the body. 

The External or Posterior Saphenous Yein, Fig. 240(7), 
commences by the external dorsal vein of the foot, which 
communicates by quite a large branch with the internal dor- 
sal vein; thus a sort of an arch is formed, from the extremi- 
ties of which the saphenous veins take their origin. It passes 
backwards and upwards around the lower and posterior sur- 
face of the external malleolus to the outer border of the tendo- 
Achillis; it then ascends on the back of the leg over the 
gastrocnemius muscle to the popliteal region. It receives on 
the dorsum of the foot, at the outer part of the ankle-joint, 
the small veins which correspond to those received by the 
internal saphenous. It is accompanied by the external 
saphenous nerve which the vein crosses twice in its course, 
passing between it and the skin. 

There are several cutaneous nerves distributed to the in- 
tegument on the back and inner part of the leg. They have 
been noticed incidentally in connection with the dissection 
of the thigh and the popliteal region. 

The CoMMUNiCANS TIBIALIS, a branch of the internal 
popliteal, and the Communicans Peronei, a branch of the 
external popliteal, Fig. 235, were observed in the dissection 
of the popliteal space. They are very regular in their origin 
and in the upper part of their course, but not so in the latter 
part of their course. Sometimes the peroneal communicans 
merely sends a branch to join the tibial communicans, and 
then again it terminates in it. They vary as to the point 
where they perforate the deep fascia, sometimes not doing it 
until they reach the lower part of the leg ; the distribution, 
however, is the same. The tibial communicans, after it has 
received the anastomosing branch from the peroneal commu- 
nicans, or has been joined by the nerve itself, is by some 
called the external saphenous. Fig. 235 (e, e). It descends on 
the outer side of the tendo-Achillis in company with the ex- 
ternal saphenous vein, to a point behind the external malleo- 
lus, where it sends off external calcaneal branches to the inte- 
gument on the heel ; it then continues forwards below the 



POSTERIOE AND INNER PART OF THE LEG. 555 

malleolus to the outer part of the dorsum of the foot, and 
divides into two branches^ one to supply the external part of 
the little toe, and the other, the contiguous surfaces of the 
same toe and the fourth toe ; the last-named division receives 
an anastomosing branch from the musculo-cutaneous nerve. 
When the peroneal communicans continues down the leg, it 
usually terminates in supplying branches to the outer part 
of the heel ; it gives off branches to the integument as it 
passes down the leg. It also frequently sends off a malleolar 
branch which, passing over the external malleolus, either 
anastomoses with, or takes the place of, a branch from the 
musculo-cutaneous. 

The Internal Saphenous IsTerve, Fig. 212 (e). Fig. 284 
(2, 2), gives off a branch named the patellar on the inner side 
of the knee, which perforates the sartorius muscle, and passing 
downwards a short distance above the tendon of the sartorius, 
turns outwards and divides into ascending^ middle, and descend- 
ing branches, which ramify on the anterior surface of the pa- 
tella, the ligamentum patellae, and the forepart of the tibia. 
After giving off the patellar branch, the saphenous passes 
over the tendon of the gracilis to join the internal saphenous 
vein, which it accompanies to the foot. Its connection with 
the vein is such as to render the dissection of either of them 
somewhat difficult, as it twines around the vein, splits and 
runs a short distance on each side of it, and then unites 
again. In its course down the leg it sends branches, both 
externally and internally, to the integument. The internal 
filaments are short, and anastomose in the upper and poste- 
rior part of the leg with filaments derived from a cutaneous 
branch given off from the internal saphenous just before it 
enters the tendinous canal formed by the adductor magnus, 
or from a cutaneous branch given off by the obturator nerve, 
which then takes the place of the one from the internal 
saphenous ; in the lower part they anastomose with filaments 
from the external saphenous nerve. The external filaments 
are long, and descend obliquely outwards in front of the 
tibia. About three or four inches above the ankle, the in- 
ternal saphenous divides into a posterior and an anterior 
branch; the former passes directly downwards in front of 
the internal malleolus to the inner part of the foot, extend- 
ing as far as the sole, and giving filaments in its course to 



556 THE LOWER EXTREMITY. 

the integument on eacli side of it; the anterior branch 
continues to accompany the saphenous vein to the dorsum 
of the foot, giving branches to the ankle-joint and to the 
skin on the foot. 

The posterior femoral cutaneous hranch of the small sciatic. 
Fig. 234 (3), terminates in filaments sent to the integument 
on the back of the leg, and also to anastomose with the 
external saphenous nerve. 

The jjeroneal cutaneous branch, Fig. 234 (5, 7), of the exter- 
nal popliteal nerve is distributed to the integument on the 
outer part of the leg. Having completed the dissection of 
the vessels ajid nerves, the superficial fascia should now be 
removed to expose the deep fascia. 

The deep fascia on the back of the leg is continuous with 
the deep fascia in the popliteal space, where it is strength- 
ened by fibrous expansions from the tendons of the biceps, 
the semi-tendinous, the gracilis, and the sartorius. It is at- 
tached laterally, to the fibula on the outer side, and to the 
inner angle of the tibia on the inner side : below, it is con- 
nected to the internal annular ligament of the ankle. There 
is another fascia on the back of the leg, which separates the 
superficial from the deep-seated layer of muscles. This will 
be noticed when it is reached in the course of the dissection. 

The internal annular ligament, Fig. 241 (14), arises from 
the margin of the internal malleolus, and is inserted into 
the internal side of the os calcis and the plantar aponeurosis. 
It spreads out so that it is much broader below than above. 
From its deep surface septa proceed inwards, to form several 
fibrous canals or sheaths for the tendons of the deep muscles 
of the back of the leg, and also for the posterior tibial nerve 
and vessels. The use of the fascia just described is to pro- 
tect the parts beneath it, and to form for the muscles sheaths, 
which increase their power of contraction ; the annular liga- 
ment keeps the tendons which pass beneath it in their proper 
position. 

The three following muscles constitute the superficial 
layer on the back of the leg. They are large, except the 
plantaris, and easily dissected. Two of them, as will be ob- 
served, arise from the femur above the articulation of the 
knee, and the third one arises from both bones of the leg, 
while they all are inserted into the os calcis. 



POSTERIOR AND INNER PART OF THE LEG. 557 

The Gastrocnemius or Gemellus, Fig. 236 (4, 4), arises 
by two lieads, an external and an internal. The internal head, 
sometimes called the gemellus internus^ is longer and larger 
than the external. It arises^ muscular and tendinous, from a 
depression and a rough surface around it on the outer and 
upper part of the internal condyle, and from a ridge that is 
formed by the bifurcation of the linea aspera; the external 
head or gemellus extemus arises from the outer and back part 
of the external condyle, and from a ridge above it. The 
tendon of each head is quite thick and. stout at its origin, 
but spreads out as it descends behind the articulation of the 
knee and on the side of the popliteal space, to join the one 
on the opposite side. The fibres which go to form the prin- 
cipal part of the belly of the muscle, have their origin on 
the anterior surfaces of these tendinous expansions. Most of 
the fibres which arise directly from the bone, end in a ten- 
dinous substance which is placed in the median line of the 
muscle, while those which arise from the tendon pass down- 
wards to be inserted into the posterior surface of a broad 
aponeurotic tendon, which gradually becomes narrower until 
it ends in the tendo-Achillis. The part of the belly formed 
by the inner head, is much thicker than that formed by the 
outer head. A synovial sac is frequently found between each 
head, most commonly the left one only, and the correspond- 
ing condyle ; in some instances they communicate with the 
knee-joint. Sometimes a sesamoid bone, or fibro-cartilage, is 
met with in one or both of the heads behind the condyle. 
The posterior surface of the gastrocnemius is convex, while 
the anterior is flattened. It forms a considerable portion of 
the calf of the leg. The tendo Achillis will be noticed in 
connection with the soleus. 

The next muscle to be dissected is the plantaris. This is 
so small, and so closely connected to the gastrocnemius, that 
the student is very liable to overlook it unless his attention 
has been directed to it. 

The Plantaris consists of a small muscular belly termi- 
nating in a long slender tendon, the longest in the body. It 
arises from a rough surface above the external condyle, and 
from ligamentous fibres placed behind it, and passes down- 
wards on the inner side of the external head of the gastro- 
cnemius, which partly covers it, and of which it frequently 



658 THE LOWER EXTREMITY. 

seems to be a part, to end about three inches below its origin, 
in a small tendon which disappears beneath the gastrocne- 
mius, to appear again on the inner side of the tendo- Achillis, 
which it accompanies to the os calcis, into which it is inserted^ 
either on the inner side of, or anterior to that tendon. The 
upper part of the tendon is placed between the gastrocne- 
mius and soleus, having, with the muscular part, a direction 
somewhat oblique from above downwards, and from with- 
out inwards. This muscle is sometimes wanting, or its ten- 
don may terminate in condensed areolar tissue before it 
reaches the heel. 

The Soleus, Fig. 236 (5, 5), is placed beneath the gastroc- 
nemius, which must be partly or wholly raised to expose it. 
This may be done by detaching both heads at their origin ; 
or by cutting across the muscle just below the junction of 
its two heads ; or by simply detaching the internal head, 
separating the muscle from the parts beneath it, and then 
turning it outwards. It is immaterial which plan is adopted, 
provided the different muscles are preserved so that they can 
be replaced after the dissection has been completed, for the 
purpose of studying their relations to each other, and more 
particularly to the vessels and nerves in this region. The 
soleus has three origins. ThQ first is by a strong tendon from 
the posterior part of the head of the fibula, and from the 
outer border and the posterior surface of the upper two 
thirds of its body; the second is from an oblique line, called 
the linea poplitei, on the posterior surface of the upper part 
of the tibia, and from the middle third of the inner angle 
of the same bone ; the third one is from a tendinous arch 
extending from the head of the fibula to the commence- 
ment of the linea poplitei. It is beneath this arch that the 
vessels and nerves pass from the popliteal space to the back 
of the leg, to get between the superficial and deep-seated 
layers of muscles, and by which they are protected from 
pressure by the action of the muscles between which they 
are placed. The fibres arising in the manner above men- 
tioned pass downwards, some of them more or less obliquely, 
to be inserted into the anterior surface of a tendinous expan- 
sion, which spreads out to form a considerable portion of the 
posterior surface of the muscle. This tendon, like the lovv^er 
one of the gastrocnemius, diminishes in breadth, but in- 



POSTEKIOR AND INNER PAET OF THE LEG. 559 

creases in thickness as it passes downwards to end in tlie 
tendo-Achillis. The muscular belly of the soleus is pro- 
longed some distance further down than that of the gastroc- 
nemius. The opposing surfaces of these muscles are per- 
fectly fitted to each other, and are separated only by loose, 
delicate areolar tissue, which allows the one to glide on the 
other with the greatest facility. Taken together, they form 
the calf of the leg ; the upper part being formed mostly by 
the gastrocnemius, the lower part by the soleus. Perhaps 
no two muscles in the body present a more beautiful appear- 
ance than these two, when fully developed and properly dis- 
sected. This is owing not only to their perfect symmetry of 
form, but to the manner in which the muscular and tendinous 
structures are distributed in them. 

The Tendo-Achillis, Fig. 236 (e), is the tendon of inser- 
tion common to the gastrocnemius and soleus. It is from 
three to four inches in length, being the largest and strongest 
tendon in the body. It is inserted into the lower part of the 
posterior extremity of the os calcis, being separated from all 
the upper and posterior surface of the bone by a synovial 
sac. It is separated from the posterior tibial vessels and 
nerve, which are placed beneath it, by areolar tissue and 
a dense fibrous membrane. The distance between it and 
the vessels allows of its being divided without any risk to 
them. 

The action of the gastrocnemius and soleus will be the 
same, as far as the ankle-joint is concerned, as both of them 
pass over it ; the former, as it passes over the knee-joint, can 
act on the leg as well as the foot, or on the thigh when the 
foot is made the fixed point. The office which they are re- 
quired to perform demands that they should be powerful 
muscles. Making their origin the fixed point, they are ca- 
pable of raising the entire body, as is done at every step that 
is taken in walking. When their attachments, and the re- 
lations which they sustain to the joints that they pass over, 
are understood, there will be no difficulty in understanding 
their actions. The action of the plantaris is so little that it 
can produce no marked effect, and as it is frequently absent, 
or when present, void of any fixed attachment below, must 
be unimportant. 

The three muscles just noticed may now be removed for 
the purpose of examining the/asc/a, which separates them 



560 THE LOWER EXTREMITY. 

from the posterior tibial vessels and nerve and tlie deep 
layer of muscles. It is an extension of the one that covers the 
poplitens muscle, downwards to the foot, where it is blended 
with the internal and external annular ligaments. Laterally, it 
is attached externally to the fibula, and internally to the inner 
border or angle of the tibia. It binds down the muscles 
which are placed under it; and should be observed with re- 
ference to the formation of pus beneath it, and the direction 
it would be most likely to take. It shows the depth of the 
posterior tibial artery, and hence may be made an important 
guide for finding that vessel. When this fascia is removed, 
the following parts will be exposed: — 

The popliteal artery will be seen at the lower border of 
the popliteus muscle, dividing into the anterior and posterior 
tibial arteries. The former is appropriated to the anterior 
part of the leg and the dorsum of the foot; the latter is dis- 
tributed mainly to the back of the leg and the plantar por- 
tion of the foot. 

The Posterior Tibial Artery, Fig. 239 (n, 12), com- 
mences at the bifurcation of the popliteal at the lower border 
of the popliteus muscle, and extends down the leg to the 
groove formed by the internal malleolus and the os calcis, 
where, beneath the internal annular ligament, or the origin of 
the abductor pollicis, it divides into the external and internal 
plantar arteries. At first it is inclined inwards for a short 
distance, after which it has a vertical direction to its termi- 
nation. In the upper part of its course it rests on the tibialis 
posticus, in the middle on the flexor longus digitorum com- 
munis, and in the lower part it is in apposition with the tibia 
and the ankle-joint. In the upper two-thirds of its course it 
is covered by the gastrocnemius and soleus muscles; in the 
lower third it lies along the inner side of the tendo- Achillis and 
the OS calcis, and is covered only by the integument and the 
different fasciae of this region, including the internal annular 
ligament. It is placed midway between the internal malleo- 
lus and the os calcis, being separated from the former by the 
tendons of the flexor longus digitorum communis and the 
tibialis posticus, and from the latter by the tendon of the 
flexor longus pollicis. The posterior tibial nerve is at first on 
the outer side, then behind, and in the lower part of the leg 
on the inner side of it, where it is separated from the artery 
by one of the venae comites. 



POSTERIOR AND INNER PART OF THE LEG. 561 



Fig. 240. 



The depth, and central position of the upper half or two 
thirds of the posterior tibial artery, and the same is true of 
the peroneal artery, as will be seen, renders it one of the most 
difficult arteries in the body to be reached in the living sub- 
ject for the purpose of applying a liga- 
ture to it. 

The posterior tibial artery gives off 
several branches in its course down the 
leg. The first one to be noticed is the 
internal recurrent branch. This passes 
round the inner border of the tibia, then 
upwards to the internal tuberosity of 
that bone, where it anastomoses with the 
inferior internal articular branch of the 
popliteal artery. The next branch to 
be observed is the nutritious artery of 
the tibia. This enters the nutritious 
foramen, and is distributed to the inter- 
nal lamellse of the bone, including the 
medullary membrane. It is remark- 
able for its large size as compared with 
other arteries of this class. Sometimes 
it is a branch of the anterior tibial 
artery. Before entering the bone, the 
nutritious artery usually gives off' one 
or more muscular branches. The next 
branch to be examined is one of the 
principal arteries of the leg. 

The Peroneal Artery, Fig. 289 
(i6, is), arises from the posterior tibial 
usually about an inch below the bifur- 
cation of the popliteal artery, and passes 



The Arteries and Deep-seated Veins on the Back of the Right Leg. 1. 

Popliteal vein. 2. Popliteal artery. 3, 4. Vein and artery in their relative position 
on the back of the knee-joint. 5. Popliteal vein on the inner side of the joint. 6. 
Popliteal artery to the outer side and beneath it. 7. Posterior or short saphenous 
vein. 8,9. Internal articular vessels, both arteries and veins. 10, 11. External 
articular vessels, both arteries and veins. 12. Junction of the peroneal and poste- 
rior tibial veins. 13. A venous branch from the anterior tibial vein. 14. A vein 
from the gastrocnemius. 15. Anterior tibial artery sroinj,' through the interosseous 
ligament. 16, 16. Posterior tibial artery. 17, 17. Its two vomv comites. IS, IS. 
Peroneal artery. 19, 19. Its two vemx) comites. 20. Vessels on the heel. 




562 THE LOWER EXTEEMITY. 

at first obliquely downwards and outwards, to penetrate the 
flexor longus pollicis muscle, in which, or between it and 
the fibula, it extends vertically to within a short distance of 
the ankle-joiot, where it divides into the posterior and ante- 
rior peroneal branches. Between its origin and the flexor 
longus pollicis, it is placed between the soleus behind and 
the tibialis posticus in front, and gives ofif in this part of 
its course branches to those muscles; a little lower down 
it supplies a nutritious branch to the fibula; and still lower, 
it sends quite a large branch to join the posterior tibial 
artery; this anastomosing branch passes transversely, or 
nearly so, across the interosseous ligament; sometimes it 
is met with very large; when this occurs, the posterior 
tibial is usually quite small above its junction with this 
branch of the peroneal artery. Besides those named, the 
peroneal artery sends branches to the peronei muscles, and 
to the periosteum on the fibula. The anterior peroneal 
branch perforates the interosseous ligament, and thus gets 
into the lower part of the anterior interosseous fossa, where 
it anastomoses with the external malleolar branch of the 
anterior tibial artery. This is an interesting anastomosis, on 
account of the large size which this branch of the peroneal 
artery sometimes presents. It occasionally takes the place 
of the anterior tibial artery in supplying the arteria dorsalis 
pedis. It sends small branches to the peroneus tertius 
muscle and to the ankle-joint, including the articulation be- 
tween the tibia and fibula. The j^osterior peroneal branch 
passes down behind the external malleolus, and over the 
ankle-joint, to reach the outer posterior part of the os calcis, 
on the surface of which it ramifies, anastomosing with 
branches of the posterior tibial, external plantar, and the 
anterior peroneal, or external malleolar branch. The integu- 
ment and adipose substance on the bottom of the heel are 
supplied principally from this branch. 

The Deep-seated Yeins, Fig. 240, on the back of the 
leg, consist of vense comites, which accompany the arteries. 
Those which accompany the peroneal artery are usually 
larger than those accompanying the posterior tibial. The 
artery is generally placed between its venae comites, between 
which frequent communications take place across the artery. 



POSTEEIOR AND INNER PART OF THE LEG. 563 

The deep-seated veins on the back of the leg nnite to form 
the popliteal vein. 

The Posterior Tibial ISTerve, Fig. 237, is a continua- 
tion of the internal popliteal, and commences at the lower 
border of the poplitens muscle, where it is placed on the 
inner side of the posterior tibial artery; as it descends in 
company with the artery it crosses over to the outer side of 
it, and continues in this position to the space between the 
internal malleolus and the os calcis, where it divides into the 
external and internal plantar nerves. In its course on the 
leg it gives off branches to the deep layer of mnscles and to 
the integument on the heel. The nerve for the flexor longns 
pollicis accompanies the peroneal artery to a short distance 
above the ankle-joint. It usually arises by a common trunk 
with the branch for the flexor longus digitorum communis. 
The branch for the tibialis posticus arises a little distance 
below the knee-joint, and a little higher than the origin of 
the branches for the other muscles; it penetrates the muscle 
near its middle, having sent filaments to it in its course to 
this point. The internal calcaneal branches arise by a sin- 
gle trunk behind the ankle-joint, winds around the os calcis, 
on its inner side, to reach the integument and adipose sub- 
stance on its lower surface, where it divides into a branch 
which goes to the posterior part of the heel, and one that 
goes to the anterior part. The relations of the posterior 
tibial nerve to the muscles are the same as those of the artery 
which it accompanies. The deep layer of muscles which are 
next to be dissected consist of four. The first one, or popli- 
teus, is covered by an aponeurosis or fascia, by the removal 
of which the muscle will be exposed. To separate the three 
muscles below this from each other, it is sometimes better to 
find their tendons first, and then trace each one upwards. It 
is not unfrequently with difficulty that any line of separation 
can be found between the upper and middle portions of these 
muscles, unless it is followed up from their tendons below ; 
this is more especially the case with the tibialis posticus and 
the flexor longus digitorum communis. 

The Popliteus, Fig. 241 (r), is a flat, triangular-shaped 
muscle, placed behind and below the knee-joint. It arises by 
a round thick tendon from a depression on the outer surfiice 
of the external condyle of the femur, just below the origin 



564 THE LOWER EXTREMITY. 

of the external head of the gastrocnemius, and the upper 
attachment of the external lateral ligament ; it passes down- 
wards and backwards beneath the external lateral ligament, 
and behind the outer part of the articulation, to the upper 
part of the tibia, into the posterior surface of which it is 
inserted^ above an oblique ridge named the linea poplitei. Its 
tendon is connected to the external semilunar cartilage by 
ligamentous fibres, and also to the synovial membrane, by 
which it is partly surrounded, and through which connection 
a communication is sometimes found to exist between the 
articulation of the fibula with the tibia, and the knee-joint. 
The action of the popliteus is to assist the hamstring muscles 
in flexing the leg on the thigh ; or it may flex the thigh on 
the leg ; it may also rotate the tibia slightly, or the femur 
when the tibia is fixed. By its connection with the semi- 
lunar cartilage, it may fix it in its proper place. 

The Flexor Longus Digitorum Communis Pedis, Fig. 
241 (7), arises from the posterior surface of the tibia, com- 
mencing just below the insertion of the popliteus and the 
origin of the soleus, and extending down to within three or 
four inches of the ankle ; it also has some fibres arising from 
the aponeurosis on the tibialis posticus, and from intermus- 
cular septa. From this origin the fibres pass obliquely back- 
wards and inwards, to end in a tendon which descends to a 
groove behind the internal malleolus, where it is covered and 
fixed in its place by the internal annular ligament, and sepa- 
rated from the tendon of the tibialis posticus by a process of 
the annular ligament. It is surrounded by a synovial mem- 
brane which extends some distance above and below the 
groove. From this point it is directed forwards and a little 
outwards, to pass through a groove in the astragalus, and also 
one in the os calcis, when it enters the sole of the foot, where 
it is first joined by a slip from the tendon of the flexor longus 
pollicis, and next by the musculus accessorius ; it now divides 
into four tendons, one for each of the four smaller toes. Each 
tendon passes through a fibrous sheath lined by synovial 
membrane. This sheath corresponds to the under surface of 
the first and second row of phalanges. Each contains also 
one of the tendons of the flexor brevis digitorum communis, 
each of which is slit opposite the base of the second phalan- 
geal bone, for the transmission of the corresponding tendon 



POSTERIOR AND INNER PART OF THE LEG. 565 



of tlie long flexor, as it passes forwards, to be inserted into tlie 
base of the last phalangeal bone. 

The Flexor Longus Follicis Pedis, Fig. 241 (9), is placed 
to the onter side of the preceding muscle, from which it is partly 
separated by the tibialis posticus. It arises from the lower 
two-thirds of the fibula, from the aponeurosis which covers the 
tibialis posticus, and from the interosseous 
membrane near the lower end of the fibula, ^ig- 241. 

and also from a fibrous septum between it 
and the peronei muscles. The fibres pass 
obliquely downwards and inwards, to end 
in a tendon which descends to a groove first 
on the inner side of the astragalus, and 
then of the os calcis, being kept by a strong 
fibrous sheath, firmly applied to these bones; 
from this point it is continued into the sole 
of the foot, and through it to the base of 
the last phalangeal bone of the great toe, 
into which it is 'inserted. Its tendon crosses 
above that of the long common flexor of 
the toes, and gives to it a tendinous slip ; in 
the latter part of its course, it is placed be- 
tween the bellies of the short flexor of the 
great toe. Opposite the internal malleolus, 
it is separated from the tendon of the long 
common flexor of the toes and the tendon of 
the tibialis posticus, by the posterior tibial UllxW '\ 

vessels and nerve. The peroneal vessels are Ik ill 

placed between its origin from the fibula, 
and its origin from the aponeurosis on the 
inner side of that bone. Its tendon passes 
very nearly through the whole muscle. Its 
action is to flex the , great toe, and, having 

The dekp Layer of Muscles op the Posterior Tibial Pegton or the Left 
Leg. — 1. The lower extremity of the femur. 2. The ligamentuiu postieum Wins- 
lowii. 3. The tendon of the semi-membranosus muscle dividing into its three slips. 
4. The internal lateral ligament of the knee-joint. 5. The lung external lateral 
ligament. 6. The popliteus muscle. 7. The flexor longus digitorum. S. Tho 
tibialis posticus. 9. Tho flexor longus pollicis. 10. Tho poroneus longus muscle. 
11. Tho peroneus brovis. 12. The tcndo-Achillis divided near its insertion into 
the OS calcis. 13. The tendons of the tibialis posticus and flexor longus digitorum 
muscles, just as they are about to pass beneath the internal annularligamont (14) 
of the ankle; the interval between the latter tendon and the tendon of tho flexor 
longus pollicis is occupied by the posterior tibial vessels and nerve. 

48 



566 THE LOWEE EXTREMITY. 

done this, to extend the foot on the leg, and to adduct the 
foot. 

The Tibialis Posticus, Fig. 241 (s), is situated in the 
middle of the interosseous fossa, or rather occupies a large 
portion of it, except at the lower part, where it has become 
tendinous. It arises from both bones of the leg, and from 
the interosseous membrane ; from the fibula, it arises between 
the origin of the soleus muscle and the outer malleolus, 
from the tibia, below the linea poplitei, and from nearly 
the whole of the posterior surface of the interosseous mem- 
brane; it also arises from the intermuscular septa, which 
separate it from the two preceding muscles. The fibres, which 
arise from these different points, pass downwards to end in a 
tendon which extends nearly the Avhole length of the muscle, 
occupying the central part of it. This tendon passes between 
that of the flexor longus digitorum communis and the tibia, 
to get into a fibrous canal above and behind the internal 
malleolus, and to the inner side of the tendon of the last- 
named muscle ; it then continues obliquely forwards and is 
inserted into the scaphoid and the internal and middle cunei- 
form bones ; sometimes some fibres can be traced from it to 
the base of the metatarsal bone of the great toe, and also to 
the external cuneiform bone. A sesamoid bone, or fibro- 
cartilage, is very frequently found in its tendon just behind 
its insertion into the scaphoid bone. A synovial membrane 
is placed between this sesamoid body and the scaphoid bone. 
The upper end of the muscle is notched for the passage of 
the anterior tibial vessels. Its action is to extend the foot 
on the leg; it will also invert the plantar surface of the foot 
by elevating its inner border ; with the long flexor muscles of 
the toes it may act as a substitute for the gastrocnemius and 
soleus in case the tendo-Achillis has been injured. It also 
assists in steadying the foot in standing or walking. 

Having completed the dissection of the back of the leg, the 
student should revze?/; what he has been over, including in 
this review the popliteal space. He should carefully examine 
the deepfascice to see in what manner they would limit or favor 
in any particular direction, the extension of collections of 
pus. He will notice that pus, collected beneath the deep fascia 
of the popliteal space, might extend to the foot without en- 
countering any obstruction from fascia ; and also that in en- 



POSTERIOR AND INNER PART OF THE LEG. 567 

tering the leg it would pass down in the sheath of the super- 
ficial layer of muscles ; or, if it should form beneath the fascia 
which covers the deep layer of muscles, it might pass under 
the internal annular ligament and enter the sole of the foot. 
Thus it will be seen that the cavity formed by the sheath of 
the superficial layer of muscles communicates with that form- 
ed by the fascia lata of the thigh, while that formed by the 
sheath of the deep layer communicates with that formed by 
the plantar aponeurosis. 

He should examine the different arteries of this region, 
and study their relations to prominent points which can 
always be seen or felt in the living subject, and by which he 
will be enabled at any time to locate any one of these ves- 
sels ; and also, such points as will serve for guides in finding 
either one of the arteries in case he should ever have occasion 
to ligate them in his practice. Take, for example, the pos- 
terior tibial artery two or three inches below its origin ; he 
should carefully examine its relations to the gastrocnemius 
and soleus muscles, in order to determine whether it could 
be reached better by cutting directly upon it through those 
muscles, or by detaching the soleus from the tibia or fibula, 
and then following the fascia which separates the superficial 
from the deep layer of muscles. He has already seen in the 
dissection of these parts that this fascia covered the artery ; 
he has also seen the position of the nerve, so that he would 
be able to take this into consideration in deciding the best 
way to reach the artery without injuring the nerve. He 
should likewise study the relations of the same artery lower 
down ; and, also, the peroneal artery. The position of the 
tendons of the long muscles of the foot as they pass through 
the sulcus formed, on the inner side by the internal malleolus, 
and on the outer side by the tendo-Achillis and the os calcis, 
should receive special attention. It may happen to him 
some time that he will have occasion to divide one or more 
of these tendons. A short time devoted to the study of these 
parts, now they are before him, may prove to be of immense 
use to him at some future time, and ho cannot neglect this 
opportunity to acquire this knowledge without doing himself 
great injustice, as well as those who will have a right to de- 
mand of him the application of it to themselves. 



568 THE LOWEE EXTEEMITY. 



Sect. Y. — Dissection of the Anterioe and Outee Paets 
OF THE Leg, and the Doesum of the Foot. 

As there is so little on the dorsum of the foot that is not 
found on the leg, while almost every thing to be dissected on 
the leg, such as fascia, muscles, vessels, and nerves, not only 
extend to, but pass over the dorsum of the foot, we think it 
is better to make but one dissection of these regions. Nor is 
the number of the parts to be examined so great that the 
student cannot, if proper means be employed to preserve the 
subject from drying or decomposing, dissect them in a satis- 
factory manner while they are in a suitable condition for 
this purpose. There is, perhaps, more danger to be appre- 
hended from the parts drying and becoming hard on the foot, 
than of their decomposing, especially if a strong solution of 
chloride of zinc has been used as an antiseptic ; this can be 
prevented only by the constant use of wet-cloths kept ap- 
plied to the limb during the intervals of dissecting. The foot 
should be extended on the leg, and kept in this position by 
means of hooks ; in dissecting the muscles it will be neces- 
sary, not only to extend the foot, but to abduct it in dissect- 
ing the tibialis anticus, and adduct it in exposing the pe- 
ronei muscles. 

To remove the integument a vertical incision may be 
made, commencing at the knee and extending it down the 
leg a little to the outside of the spine of the tibia to the ankle- 
joint, and thence in a straight line on the dorsum of the foot 
to the space between the great and the second toe. Two 
transverse incisions should be made ; an upper one extending 
from the ligamentum patellae to the outer hamstring, and a 
lower one from one malleolus to the other in front of the 
ankle-joint. If the thigh and back part of the leg have 
already been dissected, it may not be necessary to make any 
new incisions, or it may be more convenient to make them 
in a different manner; the student will have no difficulty in 
determining the most convenient way, when he remembers 
that the manner in which the skin is removed has nothing to 
do with the dissection of the parts beneath it, except to get 
it out of the way as fast as, but no faster than is required to 
expose those parts, and to use it for covering them when he is 
not dissecting. Care is necessary here as well as elsewhere in 



ANTEKIOE PAKT OF LEG, DOESUM OF THE FOOT. 569 



242. 



removing it not to take np the superficial fascia witli it, if 
the subcutaneous vessels and nerves are to be examined. 

Having raised the integument on the leg as far as the in- 
ner angle of the tibia internally, and to a short distance 
behind the fibula externally, and on the foot as far as its 
inner and onter borders back to within about an inch of the 
heel, the vessels and nerves in the superficial fascia should be 
dissected. There is neither any subcutaneous artery or vein 
of sufficient size on the anterior or outer 
part of the leg, to require any special 
notice. The only nerve of much im- 
portance is the mnsculo-cutaneous^ Fig. 
242 (s), a branch of the external popli- 
teal or peroneal nerve. This nerve 
must be looked for perforating the 
deep fascia near the junction .of the 
middle with the lower third of the leg, 
and a little to the inner side of a line 
corresponding to the fibula. It is quite 
a large nerve, and with a little care 
the student cannot fail to find it ; and 
when found, it is easily traced down the 
leg, and on the dorsu.m of the foot. It 
gives off a small branch called the exter- 
nal malleolar branch, which passes over 
the external malleolus, and anastomoses 
with a branch of the external saphe- 
nous nerve. It then divides into four 
terminal hrancTies, which are distributed 
to the toes. The first one, commencing 
internally, goes to the inner side of the //\1 

great toe ; the second goes to the outer 
side of the great toe, and to the inner 
side of the second toe ; the third sup- 
plies the outer part of the second, and 
the inner part of the third toe; the 
fourth is distributed to the outer side of 
the third, and to the inner side of the 
fourth toe. The last-named branch 
anastomoses with the external saphe- 
nous, which not unfrequently supplies 



Plan of the Cutaneotts 
Nkuves on the forepart 
OF THE Leg, and the Dor- 
sum OF THE Foot. — 1. In- 
ternal or lono; saphonous, 
become subcutaneous. 2,2,2. 
Branches of the external 
popliteal. 3. Musoulo-outa- 
neous. 4. Anterior tibial. 



570 



THE LOWER EXTREMITY. 



tbis brancli, instead of the musculo-cutaneous. The branch 
that supplies the inner part of the great toe anastomoses 
with the internal saphenous nerve. The other branches 
anastomose with the anterior tibial nerve ; sometimes they 
are wanting, when their places are supplied by branches of 
the anterior tibial. The branches of the musculo-cutaneous 
not only supply the toes to which they 
Fig. 243. are distributed, but also the integument 

on the lower and forepart of the leg, and 
on the middle part of the dorsum of the 
foot. The integument on the inner part 
of the leg is supplied by branches of 
the internal saphenous. Fig. 242 (i), 
while the external popliteal, or the pe- 
roneal cutaneous, Fig. 242 (.2, 2, 2), sup- 
ply the integument on the outer part 
of the leg. 

After removing the skin from the 
dorsum of the foot, besides the nerves 
just noticed the superficial veins^ Fig. 
243, should be examined. These consist 
of an internal and an external dorsal vein^ 
which are connected across the meta- 
tarsus so as to form an arch called the 
dorsal arch. The veins of the toes empty 
into this arch ; and, also, branches from 
the internal and external plantar veins. 
The saphenous veins have their origin 
in this arch, or rather in the internal 
and external dorsal veins. There are 
other veins on the dorsum of the foot 
and on the anterior part of the leg, but 
they require no special notice ; they ter- 
minate either in the internal or external 
saphenous vein. The superficial fascia 



The Superficial Veins of the Front of the Right Leg. — 1. Internal or long 
saphenous above the leg. 2. The same vein on the inner side of the leg. 3. A 
transverse branch below the knee which receives all the venous branches from the 
front of the leg. 4. A branch which anastomoses with the deep-seated veins. 5. 
The dorsal vein on the inner side of the foot. 6. The arch formed by the inner and 
outer dorsal veins. 



\ 



AKTERIOR PART OF LEG, DORSUM OF THE FOOT. 571 

may now be dissected off to expose the deej^ fascia^ and tlie 
external and anterior annular ligaments. 

The deep fascia on the anterior part of the leg is thicker 
and stronger than on any other part. It is composed in the 
Tipper part of fibres which have an oblique direction, and 
interlace with each other; in the lower part they are circular. 
It is continuous above with the fascia lata as it is continued 
downwards in front of the knee-joint, and is also attached to 
the tubercle of the tibia; internally^ it is attached to the spine 
of the tibia; externally^ to the fibula ; and below, to the ante- 
rior annular ligament. Thus, it will be seen that it forms a 
sheath for the muscles on the anterior part of the leg ; besides 
forming a sheath common to the muscles, it sends processes or 
intermuscular septa in between them, especially in the upper 
part of the leg. The tibialis anticus and the extensor longus 
digitorum communis have, as will be seen, their origin in 
part from these intermuscular septa ; they also arise partly 
from the inner surface of the fascia, where it covers them. 

The deep fascia on the outer side of the leg is continuous 
ahove, with the fascia lata, and is attached to the head of 
the fibula ; laterally, it is attached to the tibia and fibula, 
where it assists the anterior and posterior fascia in forming 
two intermuscular septa. This fascia forms a sheath for the 
long and short peroneal muscles, and sends a process in be- 
tween them from which, as well as from the inner surface of 
the sheath, they, in part, have their origin; below, it termi- 
nates in the external annular ligament. 

The anterior annular ligament. Fig. 244 (12), consists of a 
broad fibrous band extending superficially from the internal 
malleolus and os naviculare obliquely across in front of the 
ankle-joint to the external malleolus and os calcis. As the 
deep fascia gradually increases in thickness as it approaclies 
the ligament, it is impossible to fix any distinct line of sepa- 
ration between them. It forms on the inner side next to the 
tibia a sheath for the tendon of the tibialis anticus, and an- 
other for the tendons of the extensor longus digitorum com- 
munis and peroneus tertius, which is placed lower down and 
close to the fibula. The tendon of the extensor longus polli- 
cis also passes through a sheath, which is, however, imperfectlv 
formed ; the anterior tibial vessels and nerve pass through 
the same sheath occupied by the tendon of the extensor 
longus pollicis. A fibrous band extends from the annular 



572 THE LOWER EXTREMITY. 

ligament over the dorsum of the tarsus, and supplies the 
tendons of the same muscles with sheaths, binding them 
down at the same time to the tarsus, so that each is kept in 
its proper position. This layer of fibrous structure is con- 
tinuous laterally with the plantar fascia. The sheaths of 
these tendons are lined by synovial membrane, which is also 
reflected around the tendons themselves. 

The external annular ligament^ Fig. 244 (13), extends from 
the external malleolus to the outer surface of the os calcis. 
It forms a sheath for each of the peronei muscles, which pass 
round the external malleolus. These sheaths, like the pre- 
ceding, are lined by synovial membrane. The annular liga- 
ments around the ankle-joint are extremely interesting, when 
viewed as a part of the mechanism of the ankle and foot. 
Without a knowledge of them it will be impossible for the 
student to understand properly the actions of the muscles, 
the tendons of which have a direction quite different from 
that of those portions in which their contractile power lies. 

There are four muscles on the anterior part of the leg, 
which should now be exposed. To do this the deep fascia 
may be divided by making a vertical incision, commencing 
about three or four inches below the knee and about three- 
fourths of an inch from the spine of the tibia, and extending 
it down to the annular ligament, which should be preserved 
for the present. The fascia should then be dissected laterally 
from the muscles beneath it, so that its attachments to the 
tibia and the fibula may be observed. Having done this, 
the muscles should be separated from each other, which 
should be done at first in the lower part of the leg where 
they are free. When the tibialis anticus is separated from the 
extensor longus digitorum communis below, the separation 
can be extended upwards to their origin by dividing that por- 
tion of the fascia, from the under surface of which they partly 
arise. The fascia cannot be dissected from the upper part 
of either of the above-mentioned muscles without mutilating 
them, and leaving a rough surface formed by the cut ends of 
the fibres. The fascia is here really a part of the muscle, 
being a part of its tendon of origin in an aponeurotic form. 

The Tibialis Anticus, Fig. 244 (3), is placed next to the 
tibia, occupying the inner part of the anterior interosseous 
fossa. It arises from the head of the fibula, from the inner 



ANTERIOE PART OF LEG, DORSUM OF THE FOOT. 573 



part of tlie interosseous ligament, from tlie head and tlie 
outer surface of the upper two-thirds of the tibia, and from 
the deep fascia. The fibres pass obliquely downwards and 
inwards to end at the lower part of the leg in a flattish 
round tendon, which passes down in. front of the lower part 
of the tibia and the ankle-joint to get to the inner side of the 
tarsus, to be inserted into the tuberosity of the internal cunei- 
form bone, and by a tendinous fascicu- 
lus into the base of the metatarsal ^^g- 244. 
bone of the great toe. The fibres join 
the tendon much lower down behind 
than before, so that in front the tendon 
is seen as high as the junction of the 
middle and lower thirds of the leg; 
it extends considerably higher, but is 
concealed by the fibres of the muscle. 
It passes through a separate sheath 
formed by the anterior annular liga- 
ment, and is surrounded in the sheath 
by synovial membrane. Its action is 
to flex the foot upon the leg, to raise 
the inner part of the foot, and also to 
adduct it. As a flexor it antagonizes 
the tibialis posticus, so that when the 
student has learned its action as such, 
he has merely to reverse it to under- 
stand the action of the posticus. 

The Extensor Longus Digitorum 
Pedis, Fig. 244 (4), is situated in the 
outer part of the interosseous fossa, 
having nearly the same relation to the 
fibula that the preceding muscle has 
to the tibia. The lower part of it is 
separated from the fibula by the pero- 




The Muscles of the Anterior Tibial Region anp Dorsfm op the Foot. — 
1. The extensor muscles inserted into the patella. 2. The subcutaneous surface of 
the tibia. 3. The tibialis anticus. 4. The extensor longus digitorum. 5. The ex- 
tensor proprius pollicis. 6, The peronous tortius. 7, The peroneus longus. 8. 
The peroneus brevis. 9, 9. The borders of the soleus muscle. 10. A part of the 
inner belly of the gastrocnemius. 11. The extensor brevis digitorum; the tendon 
in front of this number is that of the peroneus tertius, and those behind it, the ten- 
dons of the peronei brevis and longus. 12. Anterior annular ligament. 13. Ex- 
ternal annular ligament. 1-i. Ligamoutum patella). 



574 THE LOWER EXTREMITY. 

neus tertius, which on the leg appears to be a part of this 
muscle. It arises from the outer part of the head of the 
tibia, from the whole of the inner surface of the u.pper half 
of the fibula including the head, from the interosseous liga- 
ment, and from the intermuscular septum on each side, and 
the deep fascia of the leg in front. The fibres from these 
different origins pass downwards, some obliquely and others 
vertically, to end in a tendon near the junction of the middle 
and lower thirds of the leg. This tendon immediately di- 
vides into three others, which pass through a single canal 
under the annular ligament, and then continue forwards on 
the dorsum of the tarsus, the external one dividing into two to 
reach the outer four toes, into the last two phalanges of which 
they are inserted. If the upper part of this muscle be de- 
tached from the fascia which covers it and the intermuscular 
septa on its sides, the surfaces thus formed will be very 
rough. On the dorsum of the foot, the four tendons cross 
over at an acute angle, from within outwards, the tendons of 
the short extensor of the toes ; each tendon spreads out on 
the dorsum of the first phalangeal bone, which it passes over 
to divide at the articulation of this bone with the second, 
into three parts, the middle one of which is inserted into the 
base of the second phalangeal bone, while the other two pass 
forwards, to be inserted in common into the base of the last 
phalangeal bone. The action of this muscle is to extend the 
toes with which it is connected, and to flex the foot on the 
leg ; it may also assist the tibialis anticus in inverting the 
sole of the foot. 

The Peroneus Tertius, Fig. 244 (e), is placed to the 
outer side of the preceding muscle, of which it not unfre- 
quently seems to be a part. It arises from the anterior and 
inner part of the lower half of the fibula, soon forms a ten- 
don which passes downwards through the same canal under 
the annular ligament as the extensor longus digitorum ; it 
then descends obliquely outwards over the tarsus to reach 
the base of the fifth metatarsal bone, into which it is inserted. 
A tendinous band sometimes connects the tendon of this 
muscle with the outer tendon of the preceding muscle. Its 
principal action is to elevate the outer border of the foot; 
in this way it may antagonize the action of the long ex- 
tensor muscles of the toes, as far as those muscles may tend 



ANTEEIOR PART OF LEG, DORSUM OF THE FOOT. 575 

to invert tTie sole of tlie foot; it may also assist in extend- 
ing the fifth toe, or in flexing the foot on the leg. 

The Extensor Pollicis Proprius, Fig. 244 (5), is placed 
between the tibialis anticus on the inner side, and the exten- 
sor longns digitorum on the outer side; the upper part of 
it is covered by these muscles. It arises from the inner 
surface of the fibula, commencing usually as high as the 
junction of the upper and middle thirds, and from the inter- 
osseous ligament close to the fibula; it may also be joined by 
a few fibres which arise from the lower part of the tibia. 
The fibres terminate in a tendon which, commencing higher 
in front than behind, passes first under the annular ligament, 
then forwards over the tarsus and the metatarsal bone of the 
great toe, to be inserted by two fasciculi into the base of the 
first phalangeal bone, and by one fasciculus into the base of 
the second phalangeal bone. Its relations to the anterior 
tibial artery are interesting, and will be noticed in the de- 
scription of that vessel. Its action is to extend the great 
toe, and to flex the foot on the leg ; it may also assist in 
raising the inner border of the foot. 

The Extensor Brevis Digitorum, Fig. 244 (1 1), is placed 
on the dorsum of the foot, being the only muscle in that re- 
gion, except the interossei, that has its origin and insertion on 
the foot. It arises on the outer part of the foot from the os 
calcis and astragalus by a short round tendon and some mus- 
cular fibres. It passes obliquely forwards and inwards be- 
neath the tendons of the extensor longus digitorum and pe- 
roneus tertius to divide into four tendons, which are continued 
forwards to be inserted into the phalangeal bones of the inner 
four toes, the little toe having no tendon from this muscle. 
The one to the great toe is larger than either of the others ; 
it passes over the dorsal artery of the foot just before it enters 
the first interosseous space, and under the tendon of the long 
extensor of the great toe, and is inserted into the base of the 
last phalangeal bone of the great toe. The other tendons get 
beneath the corresponding tendons of the long extensor of the 
toes, and become blended with them in forming the fibrous 
sheaths which cover the dorsa of all the smaller toes. The 
action of this muscle is to extend the toes. Its direction 
being obliquely from without inwards it counteracts the 
tendency of the long extensors to draw the toes towards the 



576 



THE LOWEK EXTREMITY. 



inner side of the leg, so that by their combined action the 
toes will be extended in a line directly backwards. 

Having now examined the mnscles on the anterior part of 
the leg and dorsum of the foot, the deep vessels and nerves 
found in this region should next be 
Fig. 245. noticed. To do this it will not, how- 

ever, be necessary to raise the muscles, 
for they can be pushed sufficiently to 
one side or the other to get to the 
vessels or nerves. The anterior tibial 
artery and veins, with their branches, 
are the only vessels; the anterior tibial 
and the muscular cutaneous, for a short 
distance, are the only nerves. 

The Anterior Tibial Artery, 
Fig, 245 (3 ,4 , s), is one of the divisions 
of the popliteal artery. It passes im- 
mediately through an opening in the 
upper part of the interosseous liga- 
ment, to get into the anterior interos- 
seous fossa or space, in which, resting 
on the anterior surface of the interos- 
seous ligament, it passes downwards 
to the ankle-joint, where it terminates 
in the dorsal artery of the foot. It is 
placed, in the upper third of its course, 
between the tibialis anticus and the 
extensor longus digitorum ; below this, 
down to about the middle of the lower 
third, it is found between the last- 
named muscle and the extensor pol- 
licis proprius, wdiile in the remainder 
of its course it is placed, at first, be- 
hind the tendon of the extensor poll- 




A View of the Anterior Tibial Artery and its Branches.— 1, 1, 1. The re- 
mains of the extensor proprius poUicis pedis muscle and tendon. 2, 2, 2, 2. Super- 
ficial branches from the popliteal artery, known as articular arteries. 3. Anterior 
tibial artery, as it comes through the interosseous ligament. 4. The same artery, 
on the middle of the leg. 5. Point where it passes under the extensor proprius 
tendon above the annular ligament. 6. Anterior recurrent branch. 7. Branch to 
the extensor communis, soleus, and peroneus longus muscles. 8, 8, 8. Other mus- 
cular branches. 9. Arteria dorsalis pedis, or continuation of the anterior tibial on 
the foot. 10. A branch of the external malleolar artery. 



ANTERIOR PART OF LEG, DORSUM OF THE FOOT. 577 

icis, and then between it and the extensor longus digi- 
torum. 

Thus, it will be seen that the extensor poUicis is placed at 
first to the outer side, then in front, and lastly to the inner 
side of this artery, which, in the upper third of the leg, can 
have no relation to this muscle whose origin begins at the 
junction of the upper and middle thirds. The student should 
notice the distance of this artery from the skin, as it descends 
to the ankle, or the depth of an incision that would reach it 
in any part of its course; he should also observe how far 
from the spine of the tibia, and in what direction an incision 
should be made, for the purpose of ligating it in the living 
subject. Besides muscular branches which are not named, 
the anterior tibial artery gives off the anterior tibial recurrent^ 
and an external and an internal malleolar hranch. 

^\iQ anterior tibial recurrent branchy Fig. 245 (e), arises from 
the anterior tibial artery as soon as it has reached the ante- 
rior interosseous space. It passes upwards and inwards on 
the surface of the inner tuberosity of the head of the tibia, 
covered by the origin of the tibialis anticus; it then divides 
into brauches, which anastomose with the inferior external 
and internal articular branches of the popliteal artery. 

The internal malleolar branchy Fig. 246 (i u), arises just above 
the anterior annular ligament, passes inwards and down- 
wards beneath the tibialis anticus, and divides into two 
branches, one of which enters the ankle-joint, while the other 
passes over the surface of the internal malleolus, below which, 
on the inner side of the foot, it anastomoses with branches of 
the internal plantar artery. 

The external malleolar branchy Fig. 246 (i i), usually arises 
near the anterior annular ligament ; it varies, however, very 
much in its origin and distribution, and also in its size. It 
is distributed on the outer part of the foot, anastomosing 
with branches of the peroneal artery externally and with 
branches of the dorsal artery of the tarsus inferiorly; it 
usually gives off quite a large branch to the articulation of 
the ankle. 

The dorsal artery of the foot, Fig. 246 (7, 9), commences at the 
anterior annular ligament, being a continuation of the ante- 
rior tibial, and extends forwards on the tarsus to the first 
interosseous space, into which it dips to join the external plan- 
49 



578 



THE LOWER EXTREMITY. 



Fig. 246. 



Fig. 247. 




The Superficial Arteries on 
THE TOP OP THE FooT. — 1. Tibialis 
anticus muscle. 2. Extensor proprius 
pollicis pedis. 3. Extensor commu- 
nis tendon, cut off. 4. Extensor bre- 
vis digitorum pedis. 5. Anterior 
tibial artery, between the extensor 
tendons. 6. Some of its muscular 
branches, 7. Opposite to commence- 
ment of dorsal artery. 8. Opposite 
to dorsal artery of the foot. 9. Point 
where it dips to anastomose with the 
external plantar. 10, 11. Two mal- 
leolar arteries. 12, 13. Muscular 
branches of the dorsal artery of the 
foot. 14. Metatarsal artery. 15, 16, 
17. Its interosseal branches and their 
distribution. 




The Deep- seated Arteries on the tot* 
OF the Foot. — 1. Point where the anterior 
tibial reaches the foot. 2. Dorsal artery 
of the foot. 3. Pointwhereit dips to join 
the plantar arch. 4, Internal malleolar 
artery. 6. Dorsal artery of the tarsus. 6. 
A branch to the extensor breris muscle. 
7. Branches of the dorsal artery. 8. 
Branches to the ligaments. 9. Metatarsal 
artery. 10. Superior branches of the meta- 
tarsal artery. 11. Interosseous arteries. 
12. Posterior perforating branches of the 
metatarsal. 13. Plantar interosseous arte- 
ries, seen through the interosseous spaces. 
14. Anterior perforating branches of the 
metatarsal. ]5. Bifurcation of the inter- 
osseous to give the digital of the toes. 16. 
Dorsalis pollicis. 17. A digital branch 
to the inside of the great toe. 18. Bifur- 
cation of the dorsalis pollicis. l&».Its 
perforating branch. 20, 21, 22. Distribu- 
tion of the digitals. 23. Section of the 
posterior tibial. 24. Branch xjf the poste- 
rior peroneal artery. 



tar artery. It lies to the outer side of the tendon of the ex- 
tensor of the great toe, and is covered by the skin, the super- 
ficial and the deep fascia. It gives off several branches; those 



ANTERIOK PART OF LEG, DORSUM OF THE FOOT. 579 

wliicTi are directed to tlie inner part of the foot are not 
named; they vary in number, size, and distribution. They 
anastomose behind with the internal malleolar branch of the 
anterior tibial artery, and below with branches of the inter- 
nal plantar ; those which go to the dorsum of the outer part 
of the foot are the following: — 

The dorsal artery of the tarsus^ Fig. 247 (s), passes outwards 
beneath the extensor brevis digitorum and divides into 
several branches, which anastomose with the external mal- 
leolar branch of the anterior tibial, with the external plantar 
artery, and with the one next to be described. It varies in 
size and in the number of branches which it gives off. 

The metatarsal branchy Fig. 247 (9), usually arises just be- 
fore the dorsal artery of the foot disappears in the interos- 
seous space. It passes transversely outwards in a line cor- 
responding nearly to the tarso-metatarsal articulations, forming 
an arch from which branches are given off' to supply the in- 
terosseous spaces and the integument on the upper part of 
the toes. They are called the interosseous and digifhl arteries. 
There is one for each of the interosseous spaces except the 
first, which is supplied directly from the dorsal artery of the 
foot. Each interosseous artery divides into two digital 
branches, which are distributed to the opposing sides of the 
two toes which correspond to the artery. The relations and 
distribution of the three interosseous arteries are nqyj nearly 
similar. They anastomose with branches of the correspond- 
ing arteries on the bottom of the foot. Each interosseous 
artery is joined by an anastomosing branch at each extremity 
of the interosseous space. 

The Deep Veins consist of those which accompany the 
arteries, each artery having its venoi comites. They commu- 
nicate with the superficial or subcutaneous veins at different 
points. The veno3 comites are generally arranged so as to 
have one on the outer and one on the inner side of the artery 
which they accompany; tliey communicate freel}^ with each 
other by means of branches extending between them across 
the artery. The deep veins are supplied with valves. 

The Anterior Tibial Nerve, Fig. 248 (2, 3), is one of the 
terminal divisions of the external popliteal or peroneal, which 
it leaves between the peroneus longus and the external sur- 



580 



THE LOWER EXTREMITY. 



Fig. 248. 



face of the fibula just below its head ; it then passes beneath 
the flexor longus digitorum, getting be- 
tween it and the tibialis anticus, where it 
joins the anterior tibial artery which it 
accompanies down the leg to the foot, 
being placed in front of it. Just before 
the external popliteal nerve divides into 
the musculo-cutaneous and the anterior 
tibial it gives off a small branch to the 
tibialis anticus muscle, and another to 
the tibio-fibular articulation. Below the 
anterior annular ligament the anterior 
tibial nerve divides into two branches; 
one of which accompanies the dorsal ar- 
tery to the first interosseous space, where 
it divides into two branches which are 
distributed, one to the two sides of the 
great toe, and the other to the inner side 
of the second toe. These last branches 
either anastomose with or take the place 
of the corresponding branches of the 
musculo-cutaneous nerve. The other 
terminal division of the anterior tibial 
passes obliquely outwards beneath the 
short common extensor of the toes, and 
divides into several branches, some of 
which go to that muscle, while others 
are distributed to the interosseous spaces. 

The Musculo- Cutaneous iYerre, Fig, 248 
(i), will be seen in the dissection of the 
muscles on the anterior part of the leg, 
only while passing between the peroneus 
longus and the flexor longus digitorum 
muscles; below this it perforates the deep 
fascia and becomes subcutaneous, which 
part of it has already been described in 
the superficial fascia. In the first part of 
its course it passes through the substance 
of the peroneus longus, and must be exa- 
mined when that muscle is dissected. 

On the outer part of the leg will be found the peronei 



A YIEW OF THE MuS- 
CITLO-CUTANEOUS AND 

THE Anterior Tibial 
Nerte. — 1. The mus- 
culo-cutaneous nerve. 2, 
3. The anterior tibial 
nerve accompanying the 
artery of the same name. 



i 



OUTER PART OF LEG, DORSUM OF THE FOOT. 581 

muscles, long and short. They cover the whole of the ex- 
ternal surface of the fibula except about two inches and a 
half at the lower end, where the bone is subcutaneous, and 
can be distinctly felt beneath the skin. When compared with 
the tibia, the fibula will be seen to have but little subcutaneous 
surface ; it gives origin or attachment to muscles on every 
side, while but two of the three sides of the tibia are thus 
occupied. The fibula belongs essentially to the foot, the tibia 
to both the thigh and foot, perhaps more, however, to the 
former than to the latter. Ooly one muscle passes over the 
knee-joint to be attached to the fibula, while nine will be 
found passing over it to be attached to the tibia; the reverse 
is true to some extent of the attachments of those muscles to 
the tibia and fibula which pass over the ankle-joint to the foot. 
The musculo-cutaneous nerve^ Fig. 248 (i), one of the termi- 
nal divisions of the external popliteal, should now be sought 
in the substance of the peroneus longus, in order that it may 
be traced through this muscle to the space between it and the 
extensor longus digitorum. This nerve was noticed in the 
dissection of the superficial fascia and muscles on the anterior 
part of the leg, and on the dorsum of the foot ; it only remains 
now to examine it in its course through the peroneus longus, 
and the branches which it gives off to the peronei muscles. 

The Peroneus Longus, Fig. 2i4 (7), arises from the ante- 
rior and outer surface of the head of the fibula, from a small 
portion of the external surface of the head of the tibia, from 
the outer surface of the upper half of the fibula below the 
head, from the intermuscular septum on each side of it, and 
from the fascia which covers it. From these different points 
of origin the fibres pass downwards to end in a ribbon-shaped 
tendon near the middle of the leg, where it is closely applied 
to the peroneus brevis ; becoming narrower, the tendon de- 
scends to the groove behind the external malleolus, where it 
passes under the external annular ligament in a canal with the 
short peroneus; it then turns forwards to a groove on the 
outer border of the cuboid bone, through which it passes to 
enter the sole of the foot; from this point it is directed ob- 
liquely forwards and inwards to the base of the metatarsal 
bone of the great too, into which it is inserted, Fig. 2(30 (s). 
It is covered by ligamentous fibres at the outer border of 
the cuboid bone, and also in the sole of the foot; these fibres 

41)-^- 



582 THE LOWER EXTREMITY. 

form a sheatli for it at eacli place, lined by a synovial mem- 
brane; the canal tlirongh which, it passes behind the external 
malleolus is also lined by a synovial membrane. It will be 
seen that the tendon of this mnscle passes over two trochlear 
surfaces, one behind the malleolus from which, it is reflected 
forwards and downwards, the otber at the outer border of the 
cuboid bone where it is reflected forwards and inwards. A 
sesamoid bone is frequently found in the tendon where it 
passes over the cuboid bone. The action of this muscle is to 
extend the foot on the leg and to depress the inner border of 
the foot, elevating at the same time the outer border. The 
examination of the tendon of this muscle in the sole of the 
foot must be postponed until the parts which cover it there 
have been dissected. 

The Peroneus Brevis, Eig. 244 (s), arises from the exter- 
nal surface of the lower half of the fibula, and from the inter- 
muscular septum on each side of it ; its tendon commencing 
a short distance above the external malleolus, but lower than 
that of the peroneus longus, descends to the groove behind 
the malleolus where it passes through the same canal as the 
preceding muscle; it is then continued forwards and down- 
wards through a groove on the outer side of the os calcis to 
the base of the metatarsal bone of the little toe, into which it 
is inserted; sometimes it is connected by a few fibres to the 
cuboid bone or to the base of the fourth metatarsal bone, or 
it may send a slip to the extensor tendon of the little toe. 
On the outer side of the fibula and behind the external mal« 
leolus it is placed beneath the peroneus longus, but is above 
it on the outer side of the os calcis, where it is surrounded by 
a synovial membrane. Its action is the same as that of the 
peroneus longus. These muscles should be examined with 
reference to fracture of the fibula, and, also, to displacement 
of their tendons, by being forced out of the canal through 
which they pass, behind the external malleolus. 



Sect. YI. — Dissection of the Sole of the Eoot. 

The anatomy of the sole of the foot demands the careful 
attention of the student. Its arteries and nerves, from their 



DISSECTION OF THE SOLE OF THE FOOT. 583 

exposed situation, are constantly liable to injury, especially 
among the poorer classes of people, who are in the habit of dis- 
pensing with the use of shoes or boots. Punctured wounds 
are frequently met with in the sole of the foot, which, are 
liable to be followed by tetanus, or by collections of pus ; in 
either case, the proper treatment must be based mainly on the 
anatomy of the parts. The same is true in the case of incised 
wounds, in which hemorrhage occurs, requiring the employ- 
ment of prompt and efficient means for arresting it. Deformi- 
ties are also met with, in the treatment of which a thorough 
knowledge of the foot is demanded. And the same may be 
said in regard to injuries of various kinds, requiring surgical 
treatment. The question, as to the removal of a part or the 
whole of the foot by excision or amputation, must frequently 
be decided by the extent of injury which the parts have sus- 
tained ; and, to be able to determine this, the surgeon must 
have an accurate knowledge of all the parts involved. In the 
management of such cases, the surgeon cannot rely on any 
rules which he may have learned in the lecture-room or in 
books ; for it is impossible to lay down any set of rules which 
will meet the indications of every case that may occur. Whe- 
ther the patient shall lose the whole or a part of his foot, or 
shall have the limb saved entire, may depend wholly upon a 
slight variation in the extent of the injury inflicted, and which 
can be detected only by the surgeon having a distinct idea of 
all the parts, and their relations to each other, which enter 
into the structure of the foot. 

To dissect the sole of the foot, a block must be placed under 
the instep, so that the foot can be fully extended on the leg, 
with the plantar surface looking upwards; it must also be 
firmly fixed in this position ; if this be neglected, the dissector 
will be constantly annoyed by the foot moving about, its own 
weight being insufficient to assist much in keeping it in the 
position required, and the integument is so closely connected 
to the aponeurosis or fascia beneath it, by numerous fibres 
prolonged from its under surface and from the subcutaneous 
adipose substance into the aponeurosis, that considerable force 
is required to divide them in raising the skin. To be able to 
make this dissection properly, the student must be provided 
with sharp scalpels, otherwise he will almost necessarily, either 
remove portions of the aponeurosis with the skin, or leave 



584 THE LOWER EXTREMITY. 

more or less of tlie adipose substance attaclied to the apo- 
neurosis. 

The Plantar Aponeurosis or Fascia covers nearly the 
whole of the under surface of the foot. It presents a pearly 
white, shining appearance, which will enable the dissector to 
distinguish it from the integument, and hence to know when 
he has reached it in making the first incision through the skin, 
or when, during the progress of the dissection, he is leaving 
nothing but the aponeurosis. It is divided into a middle^ an 
external^ and an internal 'portion ; the separation of these is 
indicated by two shallow grooves or sulci, caused, as will be 
seen, by the arrangement of the muscles which they cover. 

The middle portion is thicker than either of the others. It 
arises from the posterior inner tubercle on the under surface 
of the OS calcis, and extends to the metatarso-phalangeal ar- 
ticulation, where it divides into four parts. It increases in 
breadth from behind forwards, without, however, diminishing 
much in thickness. Laterally, its borders project upwards 
between the muscles which it covers and those covered by the 
internal and external portions, with which it unites to form 
two intermuscular septa; these are more perfect before than 
behind. Each of the processes, into which it divides ante- 
riorly, subdivides into two others, which are placed, one on 
each side of the corresponding metatarso-phalangeal articu- 
lation, so as to include between them the sheath and the 
tendons, one of the short and the other of the long common 
flexor of the toes, which pass through it; they terminate by 
becoming attached to the sheath, and to the ligaments of the 
joint. Laterally, the processes are united to each other so as 
to form arches which correspond to the anterior extremities 
of the interosseous spaces, and beneath which the digital ar- 
teries and nerves, also the lumbricales and the interosseous 
muscles, pass to reach the toes. For some distance from its 
posterior attachment, its upper or deep surface is occupied 
by the origin of a portion of the fibres of the flexor brevis 
digitorum; this fact the student must bear in mind when he 
comes to raise this portion of the aponeurosis; to do which, 
it should be carefully divided transversely, about an inch and 
a half from its origin, where it begins to be separated from 
the muscle by areolar tissue; the portion behind this point 



DISSECTION OF THE SOLE OF THE FOOT. 585 

cannot be raised except bj detacbing it from tbe fibres of the 
muscle ; hence it may be left to be raised witb tbe muscle. 

The middle portion of the aponeurosis forms a common 
sheath for the flexor brevis digitornm, flexor longus digito- 
rum, flexor longus pollicis, musculus accessorius, the lumbri- 
cales, and the plantar vessels and nerves. Being attached to 
the posterior extremity of the tarsus, and anterior extremity 
of the metatarsus, it greatly strengthens the arch of the foot 
in an antero-posterior direction, and also in an opposite direc- 
tion by some transverse fibres found in the part immediately 
below the metatarsus. It not only contributes to the strength 
of the framework of the foot, and serves to keep the muscles, 
for which it forms a sheath, in situ, but it protects the parts 
above it. 

The internal portion is thinner than the external, being so 
thin anteriorly that considerable care is requisite to preserve 
it when the integument is removed. Posteriorly, it is con- 
nected to the internal annular ligament, or the ligamentous 
arch that extends from the os calcis to the internal malleolus; 
internally, it is partly attached to the inner border of the tar- 
sus, and partly continuous with the dorsal fascia; externally, 
it is joined to the middle portion, and assists in forming the 
internal intermuscular septum. It forms a sheath, in part, for 
the muscles of the great toe, and the plantar vessels and 
nerves. Besides protecting the parts beneath it, it strength- 
ens the inner part of the foot. 

The external portion arises behind, from the external annular 
ligament, or the ligamentous arch that extends from the ex- 
ternal malleolus to the os calcis ; it is attached to the outer 
border of the tarsus, where it is also continuous with the dor- 
sal fascia. It forms, by its attachment to the cuboid bone and 
the posterior extremity of the fifth metatarsal bone, a strong 
ligamentous arch over the tendon of the peroueus longus 
where it enters the sole of the foot; internally it is connected 
to the external intermuscular septum, and to the middle por- 
tion of the aponeurosis. It covers the abductor and flexor 
brevis minimi digiti muscles. Its uses are similar to those of 
the inner portion. 

Having now exposed and studied the plantar aponeurosis, 
it must be raised in order to examine the parts placed above 
it. From what has already been said in describing the plan- 
tar aponeurosis and the long flexor muscles, together with 



586 THE LOWER EXTREMITY. 

the posterior tibial nerve and vessels on the back of the leg, 
the student has obtained some idea of what he will find above 
the aponeurosis. Two of the superficial muscles may be exa- 
mined first, as this can be done not only without injuring the 
vessels and nerves, but it will facilitate the dissection of them ; 
of these, the following muscle may be first examined, as it 
occupies the central part of the sole of the foot, and sustains 
more important relations to the vessels and nerves than any 
other in this region. Tt separates the grooves in which the 
external and internal plantar arteries are found. 

The Flexor Brevis Digitorum Perforatus, Fig. 249(5), 
arises from the under surface of the posterior and inner part 
of the OS calcis, from the intermuscular septum on each side 
of it, from the plantar fascia which covers its under surface, 
and also from the internal annular ligament. From these 
different points of origin it passes forwards to near the mid- 
dle of the foot, where it divides into four small muscles, each 
of which proceeds forwards a short distance and terminates 
in a small tendon, which is continued to the base of the se- 
cond phalangeal bone, where it divides into two slips, be- 
tween which the corresponding tendon of the long common 
flexor of the toes passes; the slips unite again, and, after 
expanding laterally, are inserted into the under surface of the 
second phalangeal bone. It corresponds, in the division of its 
tendon, to the superficial common flexor of the forearm. It 
is quite thick at its origin, where it is both fleshy and tendin- 
ous, but increases in breadth towards the middle of the foot. 
Its action is to flex the four outer toes; it may also strengthen 
the middle aponeurosis in preserving the arch of the foot. 
To expose this muscle, a transverse incision may be made 
across the middle portion of the aponeurosis, as was before 
mentioned, about an inch or an inch and a half anterior to 
its origin, taking care not to divide anything but the aponeu- 
rosis. The portion in front of the incision may next be 
raised. To do this, it may be dissected from behind forwards, 
detaching it from the intermuscular septum on each side ; or 
it may be divided longitudinally into four portions, so that 
each shall correspond to one of the four processes into which 
the aponeurosis divides anteriorly, and then dissect each por- 
tion to its subdivision into its two slips, and their attachments 
to the sheath of the tendons of the short and Ions: common 



DISSECTION OF THE SOLE OF THE FOOT. 



587 



flexors of tlie toes. In doing this, unless the dissection is very 
carefully made, one or more of the small delicate tendons of 
the short common flexor will be destroyed. This is very apt to 
occur in the first dissection which the student makes of these 
parts. The aponeurosis, behind the first incision that was 
made, can easily be separated on the sides, but not on the 
under surface of the muscle. There is no necessity, however, 
for raising this part of it, as it can be raised with the muscle. 
To raise the muscle it may be detached from the bone and 
reflected forwards, or it may be divided near its centre and 
turned, part of it backwards and part of it forwards. The 
abductor pollicis may next be exposed. The internal apo- 
neurosis should be removed by dissecting it off in the direc- 
tion of the fibres of the abductor muscle. 

The Abductok Pollicis, Fig. 249 (3), 
arises from the os calcis, from the in- Fig. 249. 

ternal annular ligament, from the plantar 
aponeurosis, and from the intermuscular 
septum between it and the flexor brevis 
digitorum. It passes forwards to end in 
a tendon which is inserted^ in common 
with the internal division of the flexor 
brevis, into the base of the first phalan- 
geal bone of the great toe. Its action, as 
its name implies, is to separate the great 
toe from the others; it may also assist in 
flexing the great toe. This muscle may 
now be turned over, but in doing so some 
care is necessary to avoid injuring the 
plantar vessels and nerves which pass 
under that portion of it which arises 
from the os calcis and the annular liga- 
ment. They can be easily preserved 
and traced beneath the origin of this 
muscle, if the vessels and nerves on the 




The First Layer of Muscles m the Sole of the Foot : this layer is ex- 



posed BY THE REMOVAL OP THE PlANTAR FaSCIA. — 1. Til 



OS caUMs. 



The pos- 



terior part of the plantar fascia divided transversely. 3. The abductor pollicis. 
4. The abductor minimi digiti. 5. The flexor brevis digitorum. (i. The tendon 
of the flexor longus pollicis muscle. 7, 7. The lumbricaJes. On the second and 
third toes, the tendons of the flexor longus digitorum aro seen passing through tho 
bifurcation of the tendons of the flexor brevis digitorum. 



588 THE LOWER EXTREMITY. 

back of tlie leg have not been destroyed. The posterior tibial 
artery has been seen to bifurcate at a point abont midway 
between the internal malleolus and the os calcis. From this 
bifurcation the external and internal plantar arteries pass for- 
wards and outwards to enter the sole of the foot. 

The internal plantar artery^ Fig. 250 (4), gets into the sulcus 
between the abductor pollicis and flexor brevis digitorum 
muscles, and passes forwards to the anterior part of the first 
interosseous space, where it usually terminates by sending 
one, and sometimes two branches, to the great toe. In its 
course it gives off branches to the muscles, to the integu- 
ment, and to anastomose with branches of the dorsal artery 
of the foot. 

The external plantar ar^ery,Fig.251(5, e), when it has reached 
the sole of the foot, turns outwards and forwards beneath the 
flexor brevis digitorum, and thus gets into the sulcus between 
the flexor brevis digitorum and the abductor minimi digiti, in 
which it continues for a short distance, then turns inwards 
across the second and third metatarsal bones and interosseous 
spaces, to reach the first interosseous space, where it anasto- 
moses with the dorsal artery of the foot. The anterior curved 
portion of it is called the plantar arch. At first, it passes, as 
has already been seen, under the abductor pollicis, then through 
the posterior part of the internal groove where it can be 
reached without dividing any muscle ; it theu passes under 
the flexor brevis digitorum and enters the external groove 
where it can again be reached without cutting through any 
muscle ; as it leaves the groove it becomes deep-seated, get- 
ting between the tendons and the common flexor muscles of 
the toes and the interosseous muscles ; so that in its course 
it is in three places situated beneath muscles, and in two 
places subaponeurotic. In the first and the middle part of its 
course, it gives branches to the integument on the heel, to mtcs- 
cles, and to the tarsal articulations^ also to anastomose with the 
tarsal and metatarsal branches of the dorsal artery of the 
foot. Two sets of branches are given off from the arch. 
The posterior p)erforating branches^ three in number, pass up- 
wards through the second, third, and fourth interosseous 
spaces, and anastomose with the corresponding interosseous 
arteries on the dorsum of the foot. The anterior or digital 
arteries^ Fig. 251 (14), four or five in number, pass forwards 
to supply the toes; at the anterior extremities of the inter- 



DISSECTION" OF THE SOLE OF THE FOOT. 589 

Fig. 250. Fiff. 251. 





The Deep-seated Bra^thes op the Ar- 
teries ON THE Sole of th.^' Foot. — 1. Poste- 
rior tibial artery by the side of the astragalus. 
2. Branches to the os calcis. 3. Branch of 
the posterior peroneal artery. 4. Bifurcation 
of the posterior tibial into the internal and 
external plantar. 5. The external plantar 
artery. 6. Point whore it forms the plantar 
arch. 7. Anastomosis of the anterior tibial 
•with the plantar arch. 8, 9, 10. Muscular 
branches of the external plantar artery. 11. 
Anastomosis of this artery with the metatarsal. 
12, 13. External digital of the little toe. 14. 
Digital arteries of the other toes. 15,15,15,15. 
Their disti-ibution on the toes. 16. Origin of 
the internal plantar artery. 17. Its anasto- 
mosis with the plantar arch. IS, 19, 20. Mus- 
cular branches of the internal plantar artery. 
21. Digital of the great too, or artoria magna 
poUicis, as formed by the anastomosis of the 
internal plantar and plantar arch. 22. Sub- 
articular branch of the great toe. 23. Anasto- 
mosis in the pulp of the toe. 



osseous spaces, cacli artery gives off an anterior perforating 
branch wbicb passes upwards through an interosseous space, 
and anastomoses with a correspondiug interosseous brancli. 
50 



A View op the Arteries on 
the Back of the Right Leg and 

THEIR continuation ON TO THE 

Sole op the Foot. — 1, 1, 1, 1. 
Tendons of the flexor communis 
and flexor longus pollicis pedis. 

2. Tendonof the peroneus longus. 

3. Posterior tibial artery at the 
ankle. 4, 4. External and internal 
plantar arteries. 5. Points where 
the external plantar dips to form 
the plantar arch. 6. Peroneal ar- 
tery, just above the origin of the 
external malleolar branch. 7. A 
branch to anastomose with the 
posterior tibial. 8. Just above the 
division of the peroneal artery 
into its anterior and posterior 
branches. 



590 



THE LOWER EXTREMITY. 



Fig. 252. 



The digital branches then divide, each into an internal and 
external collateral branch to go to the toes; these pass forwards 
on the opposing sides of contiguous toes. There is but one 
that goes to the outer part of the little toe. The arteria magna 
liollicis arises near the anastomosis of 
the plantar arch with the dorsal artery, 
and supplies the outer side of the great 
toe, and the inner side of the second toe. 
The veins accompany the arteries, 
there being two for each artery. They 
anastomose with the dorsal veins along 
the inner and outer borders of the foot. 
As they leave the sole of the foot they 
unite to form the posterior tibial vein. 
The nerves of the sole of the foot 
are derived from the posterior tibial 
which divides behind the internal 
malleolus into the external and inter- 
nal plantar. 

The internal plantar nerve, Fig. 252 
(4), passes along the inner side of the 
OS calcis and above the abductor pol- 
licis in company with the artery of the 
same name, and gets into the internal 
sulcus or groove, in the anterior part 
of which it divides into four digital 
branches, which supply the great, the 
second, the third, and the inner side of 




A View of the Termtn'A- 
Tiox OF THE Posterior Ti 

BiAL Nerve in the Sole of the fourth toc. Its distribution to the 

THE Foot. — 1. Inner side of , • .^ j.i j. v J.^ t 

the foot. 2. Outer side of the tocs IS the samc as that 01 the median 

foot. 8. The heel. 4. In- 
ternal plantar nerve. 5. 
External plantar nerve. 6. 
Branch to the flexor brevis 

^f?^ /• s^^°f^/^ ^\^ torum'is placed, and continues for" a 

outside of the little toe. 8. - . . t" _' . . . , 

Branch to the space between 
the fourth and fifth toes. 
9, 9, 9. Digital branches to 
the remaining spaces. 10. 



nerve is to the fingers. In the anterior 
part of its course, it perforates the 
sheath, in which the flexor breyis digi- 



short distance along the inner border 

of that muscle. It gives off several 

branches to the muscles and to the in- 

Branch to the internal side tes^ument before it divides into its ter- 

of the great toe. ^^^^^ branches. Near its origin, it 

sends quite a large branch to the integument on the heel. 

The external lAantar nerve. Fig. 252 (s), accompanies the 



DISSECTION OF THE SOLE OF THE FOOT. 591 

external plantar artery above the short common flexor, and 
in tlie external sulcus as far as the commencement of the 
plantar arch, where it divides into a superficial and a deep- 
seated hranch. The superficial branch, which is cutaneous, is 
distributed to the little toe, supplying both sides of it, and to 
the outer part of the fourth toe. The deep branch passes in- 
wards and upwards across the metatarsus, forming an arch 
similar to that formed by the external plantar artery ; it is 
distributed to the deep muscles. Frequently, it sends quite 
a large branch to anastomose with the internal plantar. It 
also sends filaments to the articulations of the tarsus and 
metatarsus. 

The Flexok Brevis Pollicis, Fig. 254 (5), arises from an 
aponeurosis which partly covers it, from the inner margin of 
the cuboid bone, from the external cuneiform, and from the 
tendon of the tibialis posticus. It divides into two bellies, 
which are inserted by short tendons into the sides of the base 
of the first phalangeal bone. A sesamoid bone is generally 
found in each of its tendons. The tendon of the long flexor 
of the great toe is placed between its bellies. 

The Flexor Accessorius or Massa Carnei Jacobi Syl- 
VII, Fig. 253 (3), arises by two heads; one, larger than the other, 
from the inner side of the os calcis, and the other from the un- 
der and anterior surface of the same bone; from these origins, 
the two heads pass forwards, soon uniting to form a single 
belly which is inserted into the outer, upper, and lower sur- 
faces of the tendon of the flexor longus digitorum just before, 
or as it divides into its four tendons. Its action is to assist 
the long flexor in flexing the toes, and to give a direction 
to the action of that muscle parallel to the axis of the foot. 
The connection between the tendons of the long common 
flexor of the toes and the long flexor of the great toe should 
now be examined, and their tendons dissected. 

The Lumbricales, Fig. 253 (4, 4), are four small muscles, 
which arise from the four tendons of the long common flexor 
near its division, and, passing along the inner side of them, 
each ends in a small flat tendon, whidi is insertedmio the inner 
and dorsal surface of the first phalangeal bone, where it also 
joins the tendon of the long extensor of the toes. The action 
of these muscles is to adduct and assist in flexing the toes, 



592 



THE LOWER EXTREMITY. 



with whicli they are connected; wlien the toes are partly 
extended, they can assist in extending them further. These 
muscles, together with the tendons of the long flexors, may 
now be removed. 



Fig. 253. 



Fig. 254. 



V 





Deep-seateb Muscles in the 
Sole of the Foot. — 1. Tendon of 
the flexor longus pollicis. 2. Ten- 
don of the flexor communis digito- 
rum pedis. 3. Flexor accessorius. 
4, 4. Lumbricales. 5. Flexor brevis 
digitorum. 6. Flexor brevis pollicis 
pedis. 7. Flexor brevis minimi di- 
giti pedis, including the abductor 
minimi digiti. 



The Third and a Part of the Second 
Layer of Muscles on the Sole op the 
Foot. — 1. The divided edge of the plantar 
fascia. 2. The flexor accessorius. 3. 
The tendon of the flexor longus digitorum. 

4. The tendon of the flexor longus pollicis. 

5. The flexor brevis pollicis. 6. The ad- 
ductor pollicis. 7. The flexor brevis minimi 
digiti. 8. The transversus pedis. 9. Inter- 
ossei muscles, plantar and dorsal. 10. Con- 
vex ridge formed by the tendon of the pero- 
neas longus muscle in its oblique course 
across the foot. 



The Adductor Pollicis, Fig. 254 (e), arises from the cu- 
boid bone and the long calcaneo-cuboid ligament, from the 
posterior extremities of the second, third, and fourth meta- 
tarsal bones, and from the sheath of the peroneus longus. It 
passes from these different origins obliquely inwards to be in- 



i 



DISSECTION OF THE SOLE OF THE FOOT. 593 

serted^ in common with the external liead of the flexor brevis 
poliicis, into the outer part of the base of the first phalangeal 
bone of the great toe. Its action is to draw the great toe 
outwards towards the other toes ; it may also, with the outer 
division of the flexor brevis poliicis, draw it downwards and 
outwards "under the other toes. 

The Teansveksalis Pedis, Fig. 254 (s), arises from the 
anterior extremities of the metatarsal bones of the four outer 
toes, passes transversely inwards between the flexor and inter- 
osseous muscles, to be inserted into the outer sesamoid bone 
with the adductor poliicis. Its action is to draw the outer toes 
towards the great toe, and prevent the metatarsal bones from 
spreading. 

The Abductor Minimi Digiti, Fig. 253 (7), arises from the 
external and inferior surface of the os calcis and the aponeu- 
rosis, which covers it ; it passes forwards along the external 
border of the foot, and is inserted into the outer part of the 
base of the first phalangeal bone of the fifth toe. Its action 
is to separate the little toe from the others, and to assist in 
flexing it. 

The Flexor Brevis Minimi Digiti, Fig.. 256 (3), arises 
from the sheath of the tendon of the peroneus longus muscle, 
from the cuboid and the fifth metatarsal bone, and, passing 
forwards and a little outwards, is inserted into the base of the 
first phalangeal bone of the little toe. Its action is to draw 
the little toe towards the others, and to assist in flexing it. 

There are seven interosseous muscles^ three of which are 
'plantar or inferior^ Siud four dorsal or superior. They are found 
in the interosseous spaces, except the plantar, which are placed 
more or less on the under surfaces of the metatarsal bones. 
The plantar muscles are called adductors, while the dorsal 
are spoken of as abductors. 

The Adductor Tertii Digiti, Fig. 256 (i), arises from the 
inner side of the tliird metatarsal bone, and is inserted into the 
inner side of the base of the first phalangeal bone of the 
middle toe. Its tendon is also blended with the tendons of 
the extensor muscles of the toes. 

The Adductor Quarti Digiti, Fig. 256 (2), arises from 
the inner side of the fourth metatarsal bone, and is inserted 

50* 



594 



THE LOWEK EXTREMITY. 



into the inner side of the base of the first phalangeal bone of 
the fourth toe, and also into the tendons of the extensor 
muscles. 

The Adductor Minimi Digiti, Fig. 256 (3), arises from the 
inner side of the fifth metatarsal bone, and is inserted into the 
first phalangeal bone of the little toe. This muscle is very fre- 
quently inseparably connected with the flexor brevis minimi. 



Fig. 255. 



Fig. 256. 





Dorsal Interosset. — 1. Abductor 
internus secundi. 2. Abductor externus 
secundi. 3. Abductor tertii. 4. Ab- 
ductor quarti. 



Plantar Interossel — 1. Adductor 
tertii. 2. Adductor quarti. 3. Adductor 
minimi digiti. 



The dorsal or superior interosseous muscles are found on 
the dorsum of the foot. They arise by two heads. They are 
usually considered abductor muscles^ the median line of the 
foot, which corresponds to the axis of the second toe, being 
taken as the line from which these muscles draw the toes. 

The Abductor Internus Secundi Digiti, Fig. 255 (i), 
arises from the outer side of the first metatarsal bone, and 
from the inner side of the second, and is inserted into the inner 



LIGAMENTS OF THE KNEE, ANKLE, AND FOOT. 595 

side of tlie base of the first phalangeal bone of the second 
toe; like the plantar, it joins the tendons of the extensor 
muscles. It draws the second to the great toe or from the 
median line of the foot. 

The Abductor Exteenus Secundi Digiti, Fig. 255 (2), 
arises by two heads from the opposite surfaces of the second 
and third metatarsal bones, and is inserted into the outer side 
of the base of the first phalangeal bone of the second toe. It 
draws the second toe from the median line of the foot. 

The Abductor Digiti Tertii, Fig. 255 (3), arises from the 
opposite surfaces of the third and fourth metatarsal bones, 
and is inserted into the outer side of the first phalangeal bone 
of the third toe. It separates the third toe from the second. 

The Abductor Digiti Quarti, Fig. 255 (4), arises by two 
heads from the opposite surfaces of the fourth and fifth meta- 
tarsal bones, and is inserted into the outer side of the base of 
the first phalangeal bone of the fourth toe. It draws the 
fourth from the third toe. 



Sect. Yll. — Dissection of the Ligaments of the Knee, 
Ankle, and Foot. 

The knee-joint is the largest of all the articulations. Fi^om 
its liability to injuries and diseases of different kinds, its study 
demands the earnest attention of every student. Before com- 
mencing the dissection of it, he should, if possible, carefully 
examine the bones which enter into its formation, or, at least, 
as far as they enter into the mechanism of the joint; it is 
better that they should be examined in an articulated skele- 
ton, as the relative position of each prominent point can then 
be observed and much better appreciated. He should also 
carefully observe the prominences and depressions around the 
joint when the limb is flexed, or extended, or placed in any 
intermediate position, so that he may be alDle, in case of dis- 
ease or injury, to detect any deviation in the general contour 
of the knee from its natural appearance. 

Three bones enter directly into the formation of the knee- 
joint; they are the /emwr, the patella, and the tihia; the fibula 
indirectly contributes to the formation of the joint, inasmuch 
as it gives attachment to tlie inferior extremities of the ex- 



596 THE LOWEE EXTREMITY. 

ternal lateral ligaments, thus compensating for the want of 
greater breadth in the upper extremity of the tibia to meet 
the corresponding diameter of the femur. There is but one 
articular surface on the femur, which may be divided into 
three parts: a trochlear surface for the patella, and two orhicu- 
lar surfaces for the glenoid cavities of the tibia; the former is 
placed in the middle anteriorly, being continuous laterally and 
posteriorly with the latter, which are placed behind, one on 
each side of the inter-condyloid notch. The glenoid cavities on 
the tibia are entirely distinct from each other, being separated 
by a prominence called the spine of the tibia, and two de- 
pressions, one behind and the other before the spine; the in- 
ter-glen oid space thus formed corresponds to the inter-condy- 
loid notch; by means of this arrangement, the two strongest 
ligaments in the joint, the crucial ligaments, are thrown into 
the central part of the articulation, thus presenting a very 
interesting feature in the mechanism of this joint. The whole 
of the posterior surface of the patella is covered by articular 
cartilage; in shape it is perfectly adapted to the trochlear 
surface on the femur, whether the leg is flexed or extended ; 
the femur moves on the patella, as the latter, owing to its liga- 
ment being inelastic, is stationary whenever the quadriceps 
extensor contracts. From the shape of the articular surfaces 
just noticed, it will be seen that flexion and extension are the 
principal movements for which they are adapted ; if the tibia 
be fixed, as in standing on one leg, the femur may be slightly 
rotated, the internal condyle turning on its axis in the corre- 
sponding glenoid cavity, as if moving on a pivot. 

In examining the parietes of the knee-joint, it is better to 
divide them into six parts or regions^ which require to be 
studied separately. By doing this, the student will be able 
to obtain a more satisfactory knowledge of the walls of this 
articulation. These parts are situated, one in front, two on 
each side, and one behind. 

The anterior region contains, in the upper part of it, the 
tendon of the quadriceps extensor muscle. Fig. 260 (2), in the 
wMclle the patella (3), and in the lower part the iigamentum 
patella?, and a considerable quantity of adipose substance (4). 
There are two Imrsce mucosoi in this region; one between the 
patella and the integument, and the other between the Iiga- 
mentum patella and the tibia, just above its tubercle (e). 

The lateral regions consist of an antero-lateralSiXidi a postero- 



LIGAMENTS OF THE KNEE-JOIKT. 597 

lateral on each side. The first of these might very appropri- 
ately be called the aponeurotic regions. In the outer one the 
parietes consist of the fascia lata, which is prolonged down- 
wards over every part of the knee, in this as well as in the 
other regions ; and beneath the fascia lata, of a thick fibrous 
layer, which is expanded from the tendon of the vastus ex- 
ternus, and, proceeding downwards, is inserted into the tibia 
between its tubercle and the lower attachments of the external 
lateral ligaments; and, under this, of a layer of fibres which 
arise from the outer border of the patella, and, passing trans- 
versely outwards, are inserted into the outer surface of the 
external condyle of the femur. The parietes in the inner 
antero-lateral region are very nearly the same as in the one 
just described; instead of the vastus externus, the vastus in- 
ternus sends off a layer of vertical fibres, which pass down- 
wards to be inserted into the tibia between its tubercle and 
the internal lateral ligament; there is no difference in the 
arrangement of the layer of transverse fibres; they are attached 
to the inner border of the patella, and to the internal condyle 
of the femur. The parietes of the joint in these regions are 
interesting on account of its being in one or the other of them 
that the cavity is entered by instruments, either in cases of 
hydrops articuli, or of loose cartilages in the joint, requiring 
an operation ; it is in these regions, also, that a bulging is first 
observed, denoting the presence of water in the joint. 

The parietes in the postero-lateral regions consist of the late- 
ral ligaments. As these ligaments are unyielding, there are 
generally depressions in hydrops articuli corresponding to 
these regions. The tendons of the inner and outer hamstring 
muscles also correspond very nearly to them. 

In the posterior region the parietes are formed by the liga- 
mentum posticum. This is very deep seated, having the con- 
tents of the popliteal space placed between it and the external 
surface. When the cavity of the joint is opened, it should be 
studied in connection with these regions. 

The ligaments of the knee-joint are divided into the external 
and internal. The former can be exposed without cutting into 
the cavity of the joint. By referring to the plates, the student 
will have no difficulty in ascertaining the exact position of 
each one. Their positions in the parietes of the joint have 
already been noticed. They will now be examined more par- 
ticularly with reference to their appearance and attachments. 



598 



THE LOWER EXTREMITY. 



The LiGAMEKTUM PATELLA, Fig. 257 (3), may be regarded 
as a continuation of the tendon of the quadriceps extensor 
cruris; so that, instead of arising from the patella, the latter 
might be considered a sesamoid bone developed in the tendon 
of the quadriceps muscle, of which the ligamentum patellae 
would be the lower part. It is attached below to the tubercle 
of the tibia, where it is considerably narrower than it is at its 
attachment to the patella. It is about two inches in length. 
By observing its white, shining appearance, the dissector will 
have no difficulty in distinguishing it from the surrounding 
parts. Whether it be considered a ligament or not, it serves 
as the medium through which the above-mentioned muscle 
acts on the leg. When the cavity of the joint has been opened 



Fig. 257. 



Fig. 258. 





An Anterioe View of the 
Ligaments of the Knee- 
joint. — 1. The tendon of the 
quadriceps extensor muscle of 
the leg. 2. The patella. 3. 
The ligamentum patellae, near 
its insertion. 4,4. The syno- 
vial membrane. 5. The inter- 
nal lateral ligament. 6. The 
long external lateralligament. 
7. The anterior superior tibio- 
fibular ligament. 



A Posterior View of the Ligaments of the 
Knee-joint. — 1. The fasciculus of the ligamentum 
postieum AVinslowii, which is derived from 2, the 
tendon of the semi-membranosus muscle ; the latter 
is cut short. 3. The process of the tendon which 
spreads out in the fascia of the popliteus muscle. 
4. The process which is sent inwards beneath the 
internal lateral ligament. 5. The posterior part 
of the internal lateral ligament. 6. The long ex- 
ternal lateral ligament. 7. The short external 
lateral ligament. 8. The tendon of the popliteus 
muscle, surrounded by synovial membrane. 9. 
The posterior superior tibio-flbular ligament. 



and examined, the ligamentum patellaa should be divided a 
short distance below the patella, Fig. 259 (s), and its relations 
to the cavity and to the tibia carefully studied ; a small hursa^ 



LIGAMENTS OF THE KNEE-JOINT. 599 

Fig. 259 (9), as was stated above, is "asually foimd separating 
it, just above its insertion, from tlie tibia. 

The ExTEKNAL Long and Short Lateral Ligaments, 
Fig. 258 (e , 7), are situated on the outer side of the joint. The 
long external lateral ligament arises from the outer and back 
part of the external condyle of the femur, close to the origin 
of the popliteus, descends anterior to the tendon of the biceps, 
and is inserted into the outer part of the head of the fibula. 
The short external lateral ligament arises nearer the back part of 
the external condyle, close to the origin of the tendon of the 
external head of the gastrocnemius, passes downwards, and is 
inserted into the posterior part of the head of the fibula. It 
is smaller, shorter, and deeper seated than the loDg ligament. 
It is connected to the semilunar cartilage, and sometimes ter- 
minates in the coronary ligament. The inferior external 
articular artery passes beneath both of these ligaments, and 
they are separated from each other by a fasciculus of fibres 
derived from the tendon of the biceps. 

The Internal Lateral Ligament, Fig. 258 (5), arises 
from the inner and posterior surface of the internal condyle 
of the femur, just below^ the insertion of the tendon "of the 
adductor magnus. It passes downwards beneath the tendons 
of the sartorius, gracilis, and semi-tendinosus, from Avhich it is 
separated by a iDursa, to be inserted into the inner part of the 
head of the tibia. Its inner surface is in relation with the 
semilunar cartilage and synovial membrane above, and the 
inferior internal articular artery below. It is a broad, flat 
ligament, being much broader, however, below than above. 

The Posterior Ligament or Lig amentum Posticum, 
Fig. 258 (1), is composed of fibres which cross the articulation 
behind in different directions; a large proportion of them, 
however, have an oblique direction from the inner and poste- 
rior part of the head of the tibia upwards and outwards to the 
external condyle of the femur ; many of these fibres are con- 
tinued from the tendon of the scmi-membranosus, forming 
what has been called the ligament of Winslow. It forms the 
floor of the central part of tlie popliteal space. Anteriorly, 
it is in relation with the scmikuiar cartihiges, synovial mem- 
brane, and the inter-condyloid notch. It is perforated by one 
or more foramina, for the transmission of the middle articular 



600 THE LOWER EXTEEMITY. 

artery, or arteries when there is more than one. It is difficult 
to make a clean dissection of this ligament, on account of the 
fat usually found intermixed with its fibres. 

To examine the interior of the knee-joint^ a semilunar in- 
cision should be made, with its concavity looking downwards, 
through the tendon of the quadriceps extensor muscle and 
the synovial membrane, about an inch above the patella, and 
extending laterally to the lateral ligaments. Having made 
the incision, and turned the patella downwards, with the leg 
semi-flexed, a beautiful view of the interior of the joint is pre- 
sented. The following parts should now be observed : — 

First, the prolongation of the synovial membrane upwards 
into a sort of pouchy between the tendon of the quadriceps 
extensor and the anterior surface of the femur, Fig. 260 (s). 
This should be carefully noted with reference to wounds 
penetrating the cavity of the joint. The extension of the 
synovial membrane upwards varies from an inch and a half 
to three inches, the difference being caused by the position 
of the leg as it regards flexion and extension ; when the leg 
is flexed, it is not more than an inch and a half or two inches, 
but is increased to two inches and a half or three inches when 
the leg is extended. Hence, to determine whether a wound 
situated two inches or a little more above the patella, has 
penetrated the cavity of the joint or not, it is necessary to 
ascertain the position of the leg at the time the wound was 
inflicted. 

Second, three folds of synovial membrane between the inter- 
condyloid notch and the upper part of the ligamentum patellas 
should be noticed. The middle one contains a few ligamentous 
fibres, and has been named the ligamentum mucosum^ Fig. 260 
(i o). The two lateral folds ^ which are frequently quite indis- 
tinct, contain adipose substance ; they have been called, with- 
out any good reason, the ligamenta alaria^ Fig. 260 (9). The 
use of the ligamentum mucosum is to hold the ligamenta alaria 
in situ^ and thus prevent them from being pinched by getting 
between the articular surfaces of the bones. From the liga- 
mentum mucosum, the synovial membrane is generally re- 
flected backwards to the crucial ligaments, so as to form a 
sort of septum dividing the posterior part of the cavity into 
a right and left portion. 

Dividing this fold, together with the ligamentum mucosum 
and also the ligamentum patellae, just below its upper attach- 



LIGAMENTS OF THE KNEE-JOINT. 601 

ment, the space between the lining membrane of the joint 
and the ligamentum patellae should be examined. It Avill be 
found to contain adipose substance, Fig. 260 (7), and the an- 
astomosis between the external and internal inferior articular 
arteries. It will be noticed that this space extends down- 
wards between the head of the tibia and the ligamentum 
patellae, and that there is at the lower part of it a bursa, Fig. 
259 (a), Fig. 260 (e), placed between the ligament and the 
bone. This space should be studied with reference to wounds 
penetrating the cavity of the joint, either directly through 
the ligamentum patellae or on either side of it. It will be 
observed that the adipose substance in this space is pressed 
backwards by the ligamentum patellae when the leg is flexed. 

To examine the reflections of the synovial memhrane in 
the posterior lower part of the cavity, a vertical section of 
the entire joint 'should be made, as represented in Fig. 260, 
or one should be made of the femur and patella, dov/n to the 
space between the semilunar cartilages on the head of the 
tibia. It will be found, when traced on the condyles, to ex- 
tend upwards a short distance beyond their articular surfaces, 
extending a little further up on the inner than on the outer 
condyle. In the posterior part of the joint, it covers, on the 
outer side, the anterior surface of the ligamentum posticum 
and the outer head of the gastrocnemius, and also the tendon 
of the popliteus. Fig. 258 (s), on which it is prolonged to the 
superior articu.lation of the tibia and fibula, with the syno- 
vial membrane of which it is sometimes connected, so as to 
form a communication between that and the knee-joint. On 
the inner side, it covers the anterior surface of the lio-amentum 
posticum and inner head of the gastrocnemius. In the central 
part of the joint behind, it is reflected upon the sides of the 
crucial ligaments, while opposite to these laterally, it covers 
the lateral ligaments. In the lower part of the joint, it is 
reflected over both the upper and lower surfaces of the semi- 
lunar cartilages, and also over the articular surfaces on the 
head of the tibia. Masses of adipose substance are observed 
in different parts of the knee-joint; they are contained in 
folds of the synovial membrane, and present different shapes; 
they have been called the synovM fringes ; they have also 
been compared to the appendices epiploicas on the colon ; 
they are even found in subjects which are greatly emaciated. 

Having traced the synovial membrane in every part of the 
51 



602 THE LOWER EXTREMITY. 

joint, the lateral and posterior ligaments may be divided, or 
removed, for tlie purpose of exposing the crucial ligaments; 
it is better to divide them, just above the convex borders of 
the semilunar cartilages, so that the connection between them 
and these cartilages may be preserved. The synovial mem- 
brane is easily detached from the crucial ligaments. These 
ligaments are two in number; as their common name implies, 
they cross each other; they are named separately the anterior 
or external^ and the -posterior or internal. From their size and 
arrangement, they contribute largely to the strength of the 
knee-joint, in the central and posterior part of which they 
are placed. 

The Anterior or External Crucial Ligament, Fig. 
259 (2), arises from the tibia just in front of the spine, be- 
tween the glenoid cavities, and passes upwards, outwards, and 
backwards, to be inserted into the inner and posterior part of 
the external condyle. 

The Posterior or Internal Crucial Ligament, Fig. 
259 (3), is somewhat larger, and more vertical in its direc- 
tion than the anterior; it arises from the tibia just behind the 
spine, and passes upwards and slightly forwards, to be inserted 
into the outer part of the internal condyle. It is placed be- 
tween the anterior crucial and the ligamentum posticum ; it 
is best seen from behind, when the latter ligament has been 
removed, while the anterior one is best seen from before. Each 
ligament is connected at its origin with one of the semilunar 
cartilages; the anterior with the anterior cornu of the in- 
ternal, and the posterior with the posterior cornu of the 
external semilunar cartilage. They limit the rotation of the 
tibia inwards, but not outwards; and prevent too great ex- 
tension of the leg on the thigh ; they also oppose abductioa 
or adduction of the leg. The crucial ligaments may now 
be divided, and the semilunar fibro-cartilages with the liga- 
ments which are connected to them for the purpose of keeping 
them in situ, may now be examined. 

There are two fibro-cartilages in the knee-joint, the In- 
ternal and External, called Semilunar, from their shape ; 
they are placed, one between each of the glenoid cavities and 
its corresponding condyle. Each presents a thick convex 
outer border, and a thin concave margin which looks towards 
the centre of the joint, where a small portion of the articular 



LIGAMENTS OF THE KNEE-JOINT. 



603 



surface of the tibia is not covered with this fibro-cartilage. 
Although these are interarticular fihro-cartilages^ they differ 
from those of other joints, as they do not form a septum 

Fig. 259. 




The Right Knee -Joint laid open from the front, in order to shov/ the In- 
ternal Ligaments. — 1. The cartilaginous surface of the lower extremity of the femur 
with its two condyles; the figure 5 rests upon the external; the figure 3 upon the 
internal condyle. 2, The anterior crucial ligament. 3, The posterior crucial liga- 
ment. 4. The transverse ligament. 5. The attachment of the ligamentum mucosum; 
the rest has been removed. 6. The internal semilunar fibro-cartilage. 7. The 
external semilunar fibro-cartilage. 8. A part of the ligamentum patellar turned, 
down. 9. The bursa, situated between the ligamentum patcllre and the head of the 
tibia; it has been laid open. 10. The anterior superior tibio-fibular ligament. 
11. The upper part of the interosseous membrane; the opening in this membrane 
is for the passage of the anterior tibial vessels. 

which divides the cavity into two compartments, but are 
covered on both sides with the same synovial membrane. 

The Internal Semilunar FiBRO-CARTiLAGE,Fig.259(R), 
is placed on the internal glenoid cavity of the tibia, and is 
applied by its superior surface to the internal condyle of the 
femur. Its borders terminate in an anterior and a posterior 
cornu, which are attached to the head of the tibia, one before 
and the other behind the spine; the anterior cornu is con- 
nected to the anterior crucial ligament. The internal lateral 
and posterior ligaments arc in apposition with its convex 
border. The synovial membrane is continuous from one 
surface to the other over its thin concave maririn. 

o 

The External Semilunar Fibro-Cartilage, Fig. 259(7), 



604 



THE LOWER EXTREMITY. 



is placed between the external glenoid cavity of tlie tibia and 
tlie external condyle of the femur; it is broader laterally 
than the internal, but not so long, being more round, which 
is owinsT to its attachments to the tibia beinsr so close to each 
other; like the internal, its upper surface is more concave 
than the lower. Its cornua are attached to the tibia, one in 
front and the other behind the spine, but between the attach- 
ments of the cornua of the internal cartilage. The posterior 
cornu is connected to the posterior crucial ligament. Its 
attached, or thick, convex border is in apposition with the 
posterior and the external lateral ligaments, and the tendon 
of the popliteus muscle. 

The semilunar iibro-cartilages are retained in situ by liga- 

Fig. 260. 




A LoxGTTUBiyAi, Section of the Left Knee-Joint, bhowino the Reflection 
OF its Synovial Membraxe. — L The cancellated structure of the lower part of the 
fe'mur. 2. The tendon of the extensor muscles of the leg. 3. The patella. 4. The 
ligamentuni patellar. 5. The cancellated structure of the head of the tibia. 6. A 
bursa situated between the ligaraentum patellae and the head of the tibia. 7. The 
mass of fat projecting into the cavity of the joint below the patella. ** The syno- 
vial membrane. S. The pouch of synovial membrane which ascends between the 
tendon of the extensor muscles of the leg, and the front of the lower extremity of 
the femur. 9. One of the alar ligaments ; the other has been removed Avith the 
opposite section. 10. Theligamentum mucosum left entire; the section being made 
to its inner side. 11. The anterior or external crucial ligament. 12. The posterior 
ligament. The scheme of the synovial membrane, which is here presented to the 
student, is divested of all unnecessary complications. It may be traced from the 
sacculus (at 8), along the inner surface of the patella; then over the adipose mass 
(7), from which it throws ofi" the mucous ligament (10); then over the head of the 
tibia, forming a sheath to the crucial ligaments; then upwards along the posterior 
ligament and condyles of the femur to the sacculus, "whence its examination com- 
menced. 



LIGAMENTS OF TIBIO-FIBULAR ARTICULATION. 605 

mentous fibres, which connect the convex border of each to 
the corresponding portion of the parietes of the joint ; these 
fibres constitute the coronary ligaments^ there being one for 
each of the fibro-cartilages. A fasciculus of fibres extends 
from one cartilage to the other in front, and assists in pre- 
venting them from being forced outwards; thej form the 
transverse ligament^ Fig. 269 (4). The cornua consist almost 
wholly of fibres which have been, where they are attached to 
the bone, named the oblique ligaments. 

It will be observed that only two of the internal ligaments 
of this joint are intended to connect the femur to the tibia, 
and to contribute directly to the strength of the articulation; 
while the others are connected with the synovial mem- 
brane and the fibro-cartilages; the latter may, at a casual 
glance, appear to be unimportant, but when properly con- 
sidered, they v/ill be found to be essential to the perfection of 
the joint. If, for instance, the ligamenta alaria are necessary 
parts of the joint, then the ligamentum mucosum is requisite 
to keep them in their proper place. The same is true of the 
semilunar fibro-cartilages and the ligamentous fibres pro- 
vided for keeping them in situ. 

Having completed the dissection of the knee-joint, the 
superior tihio-fihular articulation may be examined next. It 
is formed by a small oval articular facet on the outer and 
posterior part of the head of the tibia, and a corresponding 
one on the head of the fibula; both of these facets are covered 
with articular cartilage and with synovial membrane, which 
lines the parietes of the joint, forming a sac which sometimes 
communicates with the cavity of the knee-joint. The fact of 
a communication sometimes existing between this articula- 
tion and the knee-joint, should be recollected in a case of dis- 
articulation of the head of the fibula. Although ligamentous 
fibres surround the articulation, so as to form an imperfect 
capsular ligament, they may be described as forming an 
anterior and a posterior ligament. 

The Anterior Superior Tibio -Fibular Ligament, Fig. 
259 (1 0), consists of a broad, flat fiisciculus, which arises from 
the anterior part of the head of the fibula, and passes ob- 
liquely upwards and forwards, to bo inserted into the ante- 
rior and outer part of the tibia. 

The Posterior Superior Tibio-Fibular Ligament, Fig. 

51* 



606 



THE LOWER EXTEEMITY. 



261. 



258 (o), is not so large as the anterior.- It arises from tlie 
posterior part of tlie head of the fibula, and passes upwards 
and backwards, to be inserted into the outer and posterior 
part of the head of the tibia. The mobility allowed by this 
articulation is very limited ; the head of the fibula may move 
slightly backwards or forwards, or separate a very little from 
the tibia. 

The Interosseous Ligament or Membrane, Fig. 261 (2), 
Avhich connects the shafts of the tibia and 
fibula, forms a septum between, or a floor for, 
the anterior and posterior interosseous fossse. 
It corresponds to the one between the radius 
and ulna of the forearm. It is composed 
principally of fibres which pass obliquely 
downwards and outwards, from the outer 
angle of the tibia to the inner part of the 
fibula; a few fibres will be observed crossing 
these. An opening is observed in the upper 
part of it for the passage of the anterior tibial 
vessels ; and another at the lower part, or 
about an inch above the inferior tibio-fibular 
articulation, for the transmission of the an- 
terior division of the peroneal artery and 
its venae comites. Both of its surfaces, as 
has been observed, are occupied by the 
origins of muscles. This ligament is some- 
times called the great or superior interosse- 
ous ligament, to distinguish it from the small 
or inferior interosseous ligament VA^hich con- 
nects the lower extremities of the bones to- 
gether. 

The inferior tihio-fihular articulation is 
formed by a vertical, concave, rough surface 
on the outer part of the lower eud of the 
tibia, into which the lower end of the fibula 
is received. Instead of havinsr articular 
cartilage, covered by synovial membrane, as 

A PART OF THE FeMUR, THE PatELLA, THE BoXES OF THE LeG, AND A RAKGE OF 
THOSE OP THE FoOT OF THE LEFT SIOE ARE VIEWED IN FRONT. Some ligaments of 

the knee-joint are distinguishable. — 1. Superior anterior tibio-fibular ligament. 2. 
Interosseous membrane. 3. Inferior anterior tibio-fibular ligament. 4. Deltoid 
of ankle-joint. 6. Middle division of external lateral ; and 6, anterior division of 
same. 7. Anterior ligament of ankle-joint. 





LIGAMENTS OF TIBIO-FIBUL AK ARTICULATION. 607 

in the superior articulation, tlie articular surfaces here are 
occupied principally by ligamentous fibres, whicL. form the 
small or inferior interosseous ligament. Besides this ligament, 
they are connected by an anterior^ a posterior^ and a transverse 
ligament. 

The Anterior Inferior Tibio-Fibular Ligament, Fig. 

261 (3), arises from the outer part of the lower end of the fibula, 
passes upwards and inwards, spreading out so as to become 
quite broad, and is inserted into the outer and anterior part 
of the lower end of the tibia. It is composed of shining, 
parallel fibres which extend below the articular surfaces, so 
as to increase the depth of the cavity into which the astra- 
galus is received. 

The Posterior Inferior Tibio-Fibular Ligament, Fig. 

262 (2), consists of a fasciculus of fibres which arises from the 
posterior and lower part of the fibula, and passes obliquely 
upwards and inwards, to be inserted into the posterior and 
lower part of the tibia. It is not so large as the preceding 
ligament. 

The Transverse Tibio-Fibular Ligament, Fig. 262 (3), 
arises from the fibula, below the origin of the posterior liga- 
ment, and, passing nearly transversely in- 
wards, is inserted into the posterior part of Fig. 262. 
the internal malleolus. It increases the 
depth of the cavity formed by the tibia and 
fibula for the reception of the astragalus. 

The Small or Inferior Interosseous 
Ligament consists of fibres, intermixed with 
some adipose substance, which pass from 
the articular surface of one bone directly 
to that of the other. It is concealed by 
the anterior and posterior ligaments, which 
must be divided in order to bring it into 
view, both from behind and before. It 
adds greatly to the strength of this articula- 

A Posterior View of the Ligaments of the Ankle-Joixt. — 1. Tho lower part 
of the intorossoous mombrano. 2. Tho posterior inferior tibio-fibular ligament. ;>. 
The transverse tibio-tUnilar ligament. 4. Tho internal lateral ligament, b. Tho 
posterior fasciculus of tho external lateral ligament. 0. Tho middle fasciculus of 
tho external lateral ligament. 7. Tho synovial mombrano of the ankle-joint. S. 
Tho oa calcis. 




608 THE LOWEE EXTEEMITY. 

tion, whicli is probably stronger tliaa if both bones were 
connected at their lower extremities bj osseous matter, so as 
to form but a single piece. Articular cartilage covered with 
synovial membrane, extends a very short distance upwards 
between these bones. 

The tihio-tarsal articulation, or anlde-joint, is formed by the 
tibia and fibula above and on the sides, and the astragalus 
below and in the centre ; it belongs to the class of gingly- 
moid articulations. The tibia presents a horizontal, concave 
surface with an antero-posterior ridge, and also a vertical 
surface on the outer side of the internal malleolus, while the 
fibula also furnishes a vertical surface on the inner side of 
the external malleolus. The astragalus presents two vertical 
surfaces, one for each of the malleoli, and another which is 
concave transversely, and convex antero -posteriorly. These 
surfaces are covered with articular cartilage and synovial 
membrane. They allow of flexion and extension, and con- 
siderable lateral movement. The ligaments of this joint con- 
sist of an internal and an external lateral, and an anterior and 
a posterior ligament. These ligaments, taken together, form a 
sort of a capsular ligament, with the fibres accumulated 
principally on the sides, constituting the lateral ligaments. 

The External Lateral Ligament, Fig. 264 (e, 7, s), 
connects the fibula with the astragalus and os calcis. It con- 
sists of three distinct fasciculi, which radiate from the exter- 
nal malleolus. The anterior passes forwards and downwards, 
to be inserted into the anterior and outer part of the astraga- 
lus; it is broader at its insertion than at its origin, and it is 
shorter than the other two. The posterior passes backwards 
and slightly downwards, to be inserted into the inner and 
posterior part of the astragalus ; it is composed of parallel 
fibres arranged in several layers, being the strongest of the 
three fasciculi; the transverse tibio-fibular ligament is placed 
just above it. The middle fasciculus arises from the lower 
extremity of the external malleolus, between the origins of 
the other two, and passes downwards and a little backwards, 
to be inserted into the outer and middle part of the os calcis ; 
the tendons of the long and short peronei muscles pass 
over it. 

The Internal Lateral or Deltoid Ligament, Fig. 263 
(e), consists of a superficial and a deep layer. The former 



LIGAMENTS OF THE ANKLE-JOINT. 



609 



arises narrow from the inner and lower part of the internal 
malleolus, and, spreading out, passes downwards, some of its 
fibres being directed forwards, to be inserted into the os calcis 



Fig. 263. 





An Internal View of the Ankle- 
JoiNT — Right Leg. — 1. The internal 
malleolus of the tibia. 2, 2. Part of the 
astragalus ; the rest is concealed by the 
ligaments. 3. The os calcis. 4. The 
scaphoid bone. 5. The internal cunei- 
form bone. 6. The internal lateral or 
deltoid ligament. 7. The anterior liga- 
ment. 8. The tendo-A chillis; a small 
bursals seen interposed between the ten- 
don and the tuberosity of the os calcis. 



An External View op the Ankle- 
JoiNT — Right Leg. — 1. The tibia. 2. 
The external malleolus of the fibula. 
3, 3. The astragalus. 4. The os calcis. 
5. The cuboid bone. 6. The anterior 
fasciculus of the external lateral liga- 
ment attached to the astragalus. 7. Its 
middle fasciculus attached to the os 
calcis. 8. Its posterior fasciculus at- 
tached to the astragalus. 9. The ante- 
rior ligament of the ankle-joint. 



and scaphoides. The latter arises immediately below the for- 
mer, and is inserted into the astragalus. The tendons of the 
long flexors of the toes and the tibialis posticus pass over 
and partly conceal the lower and posterior part of this liga- 
ment. 

The Anteeior Ligament, Fig. 263 (7), is broad but very 
thin ; it arises from the lower and anterior part of the tibia, 
and passes downwards and forwards to be inserted into the 
astragalus. It is covered by the tendons of the muscles 
which pass down in front of the ankle-joint. Some care is 
requisite to preserve the fibres which compose this ligament. 

A posterior ligament of the ankle-joint can hardly be said 
to exist; its place is mainly, if not wholly, supplied by the 
transverse tibio-fibular ligament and the posterior fasciculus 
of the external lateral ligament. A good deal of adipose sub- 
stance is found outside of the synovial membrane, both in 



610 THE LOWER EXTREMITY. 

front of, and beliincl, the ankle-joint ; and, in removing it, the 
student must be careful, or he will cut through the synovial 
memlrane^ Fig. 262 (7), which is quite loose in these places, 
especially in front, and expose the interior of the joint. Fig. 
265 (9), before he desires to do so. 

Perhaps no joint in the body is more liable to injury 
than the ankle-joint, hence the importance of a thorough 
knowledge of it to the student. It should be studied with 
reference to luxations, fractures, and sprains. The mal- 
leoli form prominent points, which can alwaj^s be distinctly 
seen and felt in the living subject. Their position in relation 
to the other parts should be carefully noted, as they will be im- 
portant guides in determining whether, in cases of injury or 
disease, displacement of any part or parts has occurred, and, if 
so, its character and extent, and also whether in the treatment 
the parts displaced have been restored to their proper place. 

The tarsal ligaments^ like those of the carpus, are nume- 
rous ; and while it is scarcely expected that the student will 
have the time to become familiar with all, he should not 
neglect to acquire a thorough knowledge of som.e of them. 
A knowledge of the tarsal and the tarso-metatarsal articula- 
tions is indispensable to any one who shall have occasion to 
disarticulate the metatarsus, as in Hey's operation, or a por- 
tion of the tarsus, as in Chopart's operation. As every phy- 
sician is liable to have cases of inflammation of these joints 
and its sequelae, or of injuries not requiring, as a dernier 
resort, or at least not immediately, amputation of a portion 
of the foot, every student should avail himself of the oppor- 
tunities afforded him in the dissecting-room to carefully exa- 
mine and study the structure of the foot. Although it may 
be the last part of the limb to be dissected, it is none the less 
impoi^tant. After dissecting the muscles, vessels, and nerves 
of the whole, or any part of it, he should keep ifc wet until 
he has time to examine all the articulations, which he can 
easily do with the aid of his book and plates. 

Having severed the ligaments which connect the tibia and 
fibula with the tarsus, and dissected off all the soft parts 
which cover the bones and ligaments of the foot, the liga- 
mentous connections of the tarsus may be examined first. 
Of these, the connections of the astragalus are, from its posi- 
tion, its function, and liability to displacement, perhaps, the 



LIGAMENTS OF THE TAESUS. 611 

most important. It is connected to the os calcis by three 
ligaments, the interosseous^ the posterior^ and the external. 

Fig. 265. 




A Verticai, Section 'of the Ankle-Joint and Foot of the Right Side. — 1. 
The tibia. 2. The astragalus. 3. Os calcis. 4. The scaphoides. 5. The ciinei- 
forme internum. 6. The metatarsal bone of the great toe. 7. The first phalangeal 
bone of the great toe. 8. The second phalangeal bone of the great toe. 9. The 
articular cavity between the tibia and astragalus, with its articular adipose sub- 
stance. 10. The synovial capsule between the astragalus and os calcis. 11. The 
calcaneo-astragaloid interosseous ligament. 12. The synovial capsule between the 
astragalus and scaphoides. 13. The calcaneo-scaphoid ligament. 14. The calca- 
neo-cuboid ligament. 15. The synovial capsule between the scaphoides and cunei- 
forme internum. 16. The synovial capsule between the cuneiforme internum and 
the first metatarsal bone. 17. The metatarso-phalangeal articulation of the great 
toe, with the sesamoid bones below. 18. The phalangeal articulation of the great toe. 

The Interosseous Ligament, Fig. 265 (n), is placed in 
a canal formed by a transverse groove on the under surface 
of the astragalus, and a corresponding one on the upper sur- 
face of the OS calcis. It is a short, but very strong ligament, 
forming the principal ligamentous connection between these 
bones. Its fibres have more or less adipose substance inter- 
mixed with them. To obtain a good view of this ligament, 
a vertical section of the astragalus and os calcis should be 
made, so as to divide the ligament in an antero-posterior di- 
rection. These bones articulate with each other by mutual 
reception ; the astragalus presents two articular surfaces ; a 
concave one placed behind the groove, and a convex one 
anterior to the groove, while the os calcis presents two cor- 
responding articular focets. The articulation, posterior to 
the groove, has a distinct synovial cajisule, Fig. 265 (i o), while 
the synovial ca'psule (1.2) of the articulation in front of the 



612 



THE LOWEE EXTREMITY. 



groove is prolonged into the articulation formed by tlie 
astragalus and the scaphoides. 

The Posterior Ligament extends from the posterior part 
of the astragalus to the upper part of the os calcis. 

The External Lateral Ligament arises from the outer 
and under surface of the astragalus, and passes downwards 
beneath the middle fasciculus of the external lateral ligament, 
to be inserted into the outer part of the os calcis. The 
sheaths of the tendons of the long muscles which pass along 
the inner side of the os calcis, supply the place of an internal 
ligament. 

The astragalus is connected to the scaphoides by the 

astragalo-sca'plioid ligament. To understand properly the 

articu.lation of the astragalus with the scaphoid bone the 

external and inferior .calcaneo-scaphoid 

Fig. 266. ligaments should be considered. 

The ASTRAGALO-SCAPHOID LiGAMENT 

arises from the anterior and upper part of 
the astragalus, and passes forwards to be 
inserted into the upper surface of the 
scaphoid bone; it consists of a broad band 
of parallel fibres which cover in the articu- 
lation on the dorsum of the foot. It is 
covered by the tendons of the extensor 
muscles of the toes, and also by that of the 
tibialis anticus. 

The articulation of the astragalas with 
the scaphoid bone belongs to the class of 
enarthrodial joints, and is similar to that 
formed by the os magnum and the first 
row of bones in the carpus. It allows of 
a much greater degree of mobility than 
any other articulation in the tarsus, being 
a ball and socket joint. The cavity into 

The Ligaments of the Sole of the Left Foot. — 1. The os calcis. 2. The 
astragalus. 3. The tuberosity of the scaphoid bone. 4, The long calcaneo-cuboid 
ligament. 5. Part of the short calcaneo-cuboid ligament. 6. The calcaneo-sca- 
phoid ligament. 7. The plantar tarsal ligaments. 8, 8. The tendon of the pero- 
neus longus muscle. 9, 9. Plantar tarso-metatarsal ligaments. 10. Glenoid liga- 
ment of the raetatarso-phalangeal articulation of the great toe; similar ligaments 
are seen upon the other toes. 11, 11, 11. Lateral ligaments of the metatarso- 
phalangeal articulations. 12. Transverse ligament. 13. The lateral ligaments of 
the phalangeal bones of the great toe ; similar ligaments are seen upon the other 
toes. 




LIGAMENTS OF THE TAKSUS. . 613 

wliicli the head of the astragalus is received is formed partly 
by the inferior calcaneo-scaphoid ligament, which not only 
supports the head of the astragalus, but assists in keeping 
it applied to the glenoid cavity of the scaphoid bone. The 
synovial membrane, Fig. 265 (12), of this joint is, as was be- 
fore stated, continuous with the one in the anterior articu- 
lation of the astragalus and os calcis. 

The OS calcis is connected to the scaphoid and cuboid 
bones by several ligaments ; with the cuboid it is connected 
by a superior, an inferior, and an interosseous ligament, and 
with the scaphoid bone by two, the external calcaneo-scaphoid^ 
and the inferior calcaneo-scaphoid ligament. 

The Superior Calcaneo-Cuboid Ligament arises from 
the anterior and superior part of the os calcis, and passes for- 
wards to be inserted into the superior and posterior surface 
of the cuboid bone. 

The Inferior Calcaneo-Cuboid Ligament consists of 
two fasciculi, a long or superficial. Fig. 266(4), and a short or 
deep-seated fasciculus {^5^ The former is also called the long 
plantar ligament. They both arise from the under surface of 
the OS calcis, but have very different insertions. The long 
fasciculus extends forwards, to be inserted, partly into the 
cuboid bone, and partly into the bases of the fourth and fifth 
metatarsal bones ; it passes over and binds to the bone, the 
tendon of the peroneus longus muscle. The short or deep- 
seated fasciculus is inserted into the under surface of the 
cuboid bone, being covered by the long one below, and lying 
next to the bone above. 

The Interosseous or Internal Calcaneo-Cuboid Li- 
gament arises from the groove in the os calcis and passes for- 
wards, to be inserted into the inner and posterior part of the 
cuboid bone. It is quite a short, but a strong ligament. 

The External Calcaneo-Scaphoid Ligament arises 
from the os calcis close to the origin of the internal calcaneo- 
cuboid, and from its deep situation at its origin might, as 
well as that, be called an interosseous ligament. It is inserted 
into the upper and outer part of the scaphoid bone. 

The Inferior or Plantar Calcaneo-Scaphoid Liga- 
ment, Fig. 266 (fi ), arises from the anterior and lower part of 
the OS calcis, and passes forwards to be inserted into the 
52 



614 THE LOWER EXTREMITY. 

under surface of the scaphoid bone. It is considerably larger 
than the preceding ligament. Its upper surface is partly 
covered by the synovial membrane of the astragalo-scaphoid 
articulation, of which it may be regarded as forming a part. 

From the dissection that has now been made, the student 
will be able to see what ligaments must be lacerated, when 
the astragalus is luxated^ and also what ligaments must be 
divided in Gho'paris operation^ in which the scaphoid and cu- 
boid bones are disarticulated from the astragalus and os calcis. 
He has also seen three of the/owr synovial membranes or sacs 
which are found in the tarsus. Fig. 265 (i o, 12, 15, 1 5). 

The remaining five bones of the tarsus are connected by 
dorsal^ plantar^ and interosseous ligaments. It is not necessary 
to describe each one of these separately. With a little care 
and patience, the student will have little or no difQculty in 
finding them. 

The Scaphoid Bone is connected to the cuboid by a dor- 
sal^ an interosseous^ and a plantar ligament, all of which have 
a transverse direction. Sometimes there are one or two small 
synovial membranes between these bones, which are held 
very firmly together by their ligaments. 

The Scaphoid Bone is connected to the three cuneiform 
bones by four dorsal ligaments; one for each, except the in- 
ternal, which has two, one of which is placed on the inner 
side of the articulation, and is called the internal scaphoideo- 
cuneiform ligament; it is also connected by three plantar liga- 
ments, the principal one of which connects it to the internal 
cuneiform, and is blended with the tendon of the tibialis 
posticus. The synovial memhrane, Fig. 265 (1 5), between the 
scaphoid and cuneiform bones, is continuous with those found 
between the latter bones. 

The Cuboid Bone is joined to the external cuneiform 
bone by a dorsal, a plantar, and an interosseous ligament. 
These ligaments have a transverse direction. The plantar 
one is very small. 

The Cuneiform Bones are connected to each other by 
dorsal, plantar, and interosseous ligaments. Of these, the 
interosseous are the strongest. The plantar are very small. 
The fourth synovial membrane of the tarsus is common to 
the articulations of the cuboid with the external cuneiform, 



LIGAMENTS OF THE METATARSUS. 615 

to the scaphoid with the three cuneiform, and to the cuneiform 
with each other. The same synovial membrane is also pro- 
longed forwards between the cuneiform bones and the first, 
second, and third metatarsal bones. Fig. 265 (i e). 

The Tarso-Metataesal Articulation is formed by the 
cuboid and the three cuneiform bones^ and the five metatarsal 
bones. The middle cuneiform bone is shorter than the other 
two, and hence the second metatarsal bone projects backwards 
between the internal and external cuneiform. In disarticu- 
lating the metatarsus from the tarsus, as in I{ey''s operation^ it 
is important to recollect this arrangement. It will be seen that 
the internal cuneiform articulates with the first and second 
metatarsal, the second cuneiform with the second metatarsal, 
and the third cuneiform with the second and third metatarsal, 
while the cuboid is joined to the fourth and fifth metatarsal 
bones. These articulations allow some degree of mobility, 
especially when considerable force is used, as in jumping and 
leaping. The same is true of the articulations between the 
anterior five bones of the tarsus. Although the motion al- 
lowed by any single one of these articuhitions is very little, in 
the aggregate it amounts to considerable. 

The tarsus is joined to the metatarsus by dorsal^ ijlantar^ and 
interosseous ligaments. Each metatarsal boue, except the second, 
is connected to the tarsal bone with which it articulates by a 
dorsal ligament; the second is joined to each of the three 
cuneiform bones by a dorsal ligament, and to each of the in- 
ternal and middle by a plantar ligament. The articulation of 
the first metatarsal bone is strengthened hj fibres derived from 
the insertion of the tendons of the tibialis anticus and peroneus 
longus. The fourth and fifth metatarsal bones obtain their 
plantar ligaments from fibres derived from the sheath of the 
peroneus longus. The tendon of the peroneus brevis and 
the external division of the plantar aponeurosis assist in 
keeping the fifth metatarsal bone in its place. The inter- 
osseous ligaments are placed between the bones which they 
connect. 

The Metatarsal Bones are connected together at their 
tarsal extremities by three sets of ligaments, dorsal, iuterosscouSj 
Siud ]jlantar. The interosseous arc very strong, passing directly 
from one bone to another. The dorsal and plantar ligaments 



616 THE LOWER EXTREMITY. 

also have a transverse direction. At their phalangeal extre- 
mities they are connected by a transverse ligament. Fig. 
266(12). 

The Metatarsal Bones are connected to each of the 
phalangeal bones by two lateral^ and one glenoid ligament for 
each articulation. Fig. 266 (1 0, 11). The tendons of the ex- 
tensor muscles of the toes supply the place of the dorsal liga- 
ments. The glenoid ligaments are dense, like iibro-cartilage. 
There is one placed below each articulation, the edges of 
which are continuous with the lateral ligaments, and also with 
the sheath of the corresponding tendons of the common 
flexor muscles of the toes. Each also assists in forming the 
cavity for the reception of the head of the corresponding 
metatarsal bone. The lateral ligaments are very strong; 
each one, as well as the glenoid ligament, is connected with 
the digital processes of the plantar aponeurosis. 

The Phalangeal Bones are connected together by means 
of one glenoid and two lateral ligaments^ Fig. 266(13), for 
each joint. The glenoid ligament has the same arrangem.ent 
as in the preceding articulation, and the lateral ligaments 
also have the same attachments and the same relations as in 
that joint. As in the metatarso-phalangeal articulations, 
there are no dorsal ligaments, the tendons of the extensor 
muscles supplying their places. There is nothing connected 
with the synovial membranes in these articulations that re- 
quires any notice. 



INDEX 



Abdomen, 339 

cavity of, 360 

regions of, 360 
Abdominal ring, external, 344, 350 

internal, 354 
Acini, 400, 402 
Alimentary canal, 387 
Annulus ovalis, 302 
Anti-helix, 120 
Anti-tragus, 120 
Aorta, abdominal, 410 

arch of, 318 

descending, 315 
Aortic opening of diaphragm, 419 

of heart, 309 
Aponeurosis, brachial, 249 

costo-clavicular, 212 

of forearm, 258 

gluteal, 511 

palatine, 150 

pharyngeal, 205 

temporal, 49 

vertebral, 228 
Apparatus ligamentosus colli, 632 
Appendices epiploica), 372 
Appendix auriculaa, 302, 307 

vermiformis cseci, 371, 397 
Aqueduct of Fallopius, 124 

of Sylvius, 65 
Aqueductus cochleae, 130 
Aqueous humor, 110 
Arachnoid membrane, of brain, 53 

of spinal cord, 287 
Arbor vita? cerebelli, 73 

uterina, 487 
Arch, of colon, 372 

dorsal, 670 

femoral, deep, 499 

palmar, deep, 279 

superficial, 274 

plantar, 682 
Arciform fibres, 75 
Arm, superficial veins at bond, 218 

AUTEHIES, 

ad ciitem abdominis, 341, 490 



52-^- 



Artekies — continued. 

anastomotic of femoral, 550 

of brachial, 253 
aorta, 300 
articular of knee, 

external, inferior, 650 
superior, 550 

internal, inferior, 551 
lower superior, 550 
superior, 550 

middle, 551 
ascendens colli, 172 
auricular, 122 

posterior, 51, 184 
axillary, 212, 215 
basilar, 86 
brachial, 252 
brain, of the, 85 
bronchial, 322 
bulbar, 465 

carotid, common, left, 192, 320 
right, 192 

internal, 184 
carpal, ulnar, anterior, 264 
posterior, 264 

radial, 264 
centralis retina?, 94, 100 
cerebellar inferior, 87 

superior, 87 
cerebral, anterior, 85 

middle, 85 

i:)ostorior, SO 
cervical, posterior, 175, 227 

profound, 174, 233 

transverse, 172 
ciliary, 95, 104 
circumflex ilii, external, 490 

internal, 346, 358 

of arm, anterior, 219, 239 
posterior, 218, 222, 239 

of thigh, external, 505 
internal, 605, 543 
coccygeal, 444 
ccoliac, 373, 375 
colic, iloo-, 381 



618 



IN"DEX, 



Arterie s — continued. 
colic, left, 383 

middle, 381 

right, 381 
comes nervi, ischiadici, 444, 516 

• phrenici, 294 
communicating of brain, anterior, 
85 

of brain, posterior, 85 
coronaria, dextra, 314 

sinistra, 314 

superioris, 378 
corporis bulbosi, 429 

carernosi, 429 
cremasteric, 358 
cricoid, 183 

cutaneous of abdomen, 341 
cystic, 379, 404 
deferential, 442 
dental inferior, 113 

superior, 115 
digitales manus, 274 

pedis, 588, 590 
dorso-carpal, radial, 273 
dorsalis pedis, 577 

penis, 429 

scapulae, 218, 222, 242 
dorsal of tarsus, 579 
epigastric, 348, 355, 358 

superficial, 490 
ethmoidal, 95 
facial, 36, 50, 158, 176 
femoral, 504 
gastric, 378 
gastrocnemial, 552 
gastro-duodenal, 378 
gastro- epiploic, left, 376 

right, 379 
gluteal, 444, 514 
hemorrhoidal, inferior, 421, 457 

middle, 443 

superior, 383 
hepatic, 373, 378 
hypogastric, 439 
humeral, transverse, 172, 227 
iliac, common, 412 
external, 412 
internal, 439 
ileo-colic, 381 

-lumbar, 441 
infra-orbital, 38, 115, 117 
innominata, 168, 320 
intercostal, 233, 329, 357 
anterior, 294 
superior, 174 
interosseous, of arm, 264 
anterior, 264, 267 
posterior, 264, 271 
intestinal, large, 381 
small, 380 



Arterie s — contimied. 
ischiatic, 444 
lachrymal, 94 
laryngeal, 183 
lingual, 181 
lumbar, 233, 358, 410 
magna pollicis, manus, 279 

pedis, 590 
malleolar, external, 577 

internal, 577 
mammary, internal, 172,293,348,357 
masseteric, 111 
maxillary, internal, 112 
mediastinal, 294 
meningeal, anterior, 90, 114 

middle, 90, 113 

parra, 90 

posterior, 90 
mesenteric, inferior, 383 

superior, 379 
metacarpal, ulnar, 264 
metatarsal, 579 
musculo-phrenic, 294 
nasal, 96 
of Nebauer, 166 
obturator, 412, 441 
occipital, 51, 183, 232 
oesophageal, 329 
ophthalmic, 50, 94 
ovarian, 443 
palpebral, 95 
pancreatic, 376 

pancreatico-duodenal, 378, 380 
perforantes, femoralis, 506, 543 

of foot, 588, 589 
perineal, superficial, 462 

transverse, 462 
peroneal, 561 

anterior, 582 

posterior, 562 
pharyngeal, ascending, 183 

inferior, 183 
phrenic, 410 
plantar, external, 588 

internal, 588 
popliteal, 549 
princeps cervicis, 183. 232 
profunda, femoris, 505 

inferior of arm, 253 

superior of arm, 253 
pterygoid, 114 
pubic, 358 

pudic, external, superior, 490 
inferior, 505 
internal, 444, 466, 516 
pulmonary, 300, 306, 321, 328 
pyloric, superior, 373 
radial, 262, 273, 279 
radialis indicis, 279 
ran in e, 154 



INDEX. 



619 



Arteries — conti 

recurrent, radial, 262 

tibial, anterior, 677 
internal, 561 

ulnar, anterior, 264 
posterior, 264 
renal, 385 
sacral, middle, 411, 439 

lateral, 443 
scapular posterior, 156 
sciatic, 444, 516 
sigmoid, 383 
spermatic, 384, 435 
spinal, anterior, 288 

posterior, 288 
of the-spinal cord, 288 
splenic, 376 

subclavian, 170, 192, 330 
sublingual, 154 
submental, 159, 176 
subscapular, 218 
superficialis volse, 262 
supra-orbital, 50, 94 
supra-renal, 385 

supra-scapular, 172, 227, 240, 242 
tarsal, 579 
temporal, 50 

anterior, 50 

deep, 110 

middle, 50 

posterior, 50 
thoracica-acromial, 211, 212 

-axillaris, 218 

inferior, 214 
^ superior, 211, 212 
tibial anterior, 576 

posterior, 560 
thyroid, axis, 170 

inferior, 170, 171 

middle, 166 

superior, 183 
transverse facial, 32 
tympanic, 114, 131 
ulnar, 263 
umbilical, 439 
uterine, 443 
vaginal, 443 
vasa brevia, 376 
vertebral, 86, 173, 233 
vesical, 442 
Articulations, 

sacro-vertebral, 535 
sacro-coccj'^geal, 535 
sacro-iliac, 530 
tarsal, 610 

tarso-mctatarsal, 615 
temporo-maxillary, 115 
tibio-libular, inferior, 006 

superior, 605 
tibio-tarsal, 008 



Articulations — continued. 
metatarso-phalangeal, 616 
metatarsal, 615 
phalangeal of foot, 616 
of hand, 285 
Arytenoid cartilages, 195 
Auricle of ear, 120 

of heart, left, 300, 301, 307 
right, 300, 301, 302 
Auricula of heart, 302 • 
Auriculo-venti-icular orifice, left, 308 

right, 305 
Axillary artery, surgical relations of, 

213, 216 
Axillary region, 207 

Back, nerves of, 224 

arteries of, 224 
Bladder, female, 482 

male, 421, 436 
Bone, hyoid, 193 

turbinated, inferior, 137 
middle, 138 
superior, 138 
Brain, base of, 75 

membranes of, 52 

dissection of, 52 
Bronchial tubes, 326 
Bronchi, 322 
Brunner's glands, 394 
Bulb of corpus spongiosum, 427, 438 
Bulbi vestibuli, 480 
Bulbous part of the urethra, 426 
Bursae at wrist, 276 

Csecum, 371 

Calamus scriptorius, 68 

Calices, 407 

Canal, of Bichat, 80 

of Cloquet, 109 

of the Epididymis, 433 

of Fontana, 104 

inguinal, 352 

of Nuck, 483 

of Petit, 109 
Canals, portal, 401 
Canaliculi lachrymales, 45 
Capsule of Glisson, 400 
Capsules, supra-renal, 409 
Caput gnllinaginis, 425 
Cartilage, cricoid, 194 

thyroid, 194 
Cartilages, arytenoid, 195 
appendices, 196 

costal, 334 

intor-articular, of the clavicle, 213, 
335 

intor-nrlicular, of the jaw, 116 
of knoo, 002 

of uoso, l.')l 



620 



INDEX. 



Cartilages of nose — 

columna, 134 
lateral inferior, 135 

superior, 135 
septal, 134 
sesamoid, 135 
semilunar, 602 
tarsal, 43 
Caruncula lachrymalis, 44 
Carunculse myrtiformes, 478 
Cauda equina, 289 
Cerebellum, 69, 73 
Cerebrum, 56 

lobes of, 80 ' 
Chamber of eye, anterior, 105 
posterior, 104 
Cheeks, 144 

Chordae, tendinejB, 305, 308 
Tocales, 198 
Willisii, 55 
Choroid coat, 104 
plexus, 61, 69 
Ciliary ligament, 103 

processes, 107 
Circle of Willis, 85, 87 
Clitoris, 477 
Cochlea, 128 
Coeliac axis, 376 
Colon, ascending, 371 
descending, 372 
transverse, 372 
Columnoe carneas, 304, 308 
Commissures of brain, anterior, 64 
longitudinal superior, 57 
middle, 64 
posterior, 64 
of cord, gray, 290 
white, 290 
Concha, 120 
Coni vasculosi, 433 
Conjunctiva, 44, 102 
Conus arteriosus, 305 
Conjoined tendon, 345 
Cord, spermatic, 434 
Cornea, 102 

Cornua ventriculorum, 59, 61 
Corpora Arantii, 306, 309 
cavernosa penis, 427 

clitoridis, 477 
geniculata, 63 
mammillaria, 78 
olivaria, 74 
pyramidalia, 74 
pyramidalia posterior, 75 
restiformia, 75 
Corpus callosum, 67 

arteries of, 85 

peduncles of, 79 
dentatum, 73 
fimbriatum, 484 



Corpus fimbriatum — 

of the brain, 62 

Highmorianum, 432 

luteum, 488 

rhomboideum, 73 

spongiosum, 427 

striatum, 59 
Cowper's glands, 426, 428, 466 
Cranium, soft parts on upper part of, 47 

cellulo-adipose layer on, 47 
Cricoid cartilage, 194 
Corpuscles of Malpighi, 408 
Corona glandis, 427 
Crico-thyroid membrane, 198 
Crura cerebelli, 68 

cerebri, 77 
Crural canal, 497 

ring, 497 
Crystalline lens, 109 
Cupola of ear, 130 
Culs-de-sac of stomach, 387 
Cuneiform bodies, 197 
Cystic duct, 403 

Dartos, 430 
Diaphragm, 417 
Duct, cystic, 403 

hepatic, 401, 403 

lymphatic right, 192, 330 

pancreatic, 374, 393, 404 

of Steno, 32 

thoracic, left, 191, 315, 329 

of Wharton, 177, 179 
Ducts, of Bellini, 408 

of Rivinus, 181 
Ductus, ad nasum, 46, 137 

arteriosus, 321 

communis choledochuSj 373, 393, 
493 

ejaculatorius, 434 

venosus, 400 

yesiculte seminales, 434 
Duodenum, 370, 392 
Dura mater of cerebrum, 53, 87 
arteries of, 90 
nerves of, 90 

of spinal cord, 286 

Ear, external, 120 

internal, 127 

middle, 123 
Eminentia pyramidalis, 128 
Endocardium, 310 
Endolymph, 130 
Epididymis, 431 
Epiglottic gland, 197 
Epiglottis, 196 
Eustachian tube, 124, 139, 149, 152 

valve, 303 



INDEX. 



621 



Eye, 

appendages of, outside of orbit, 40 

within orbit, 91 
ball, 99 
brows, 40 
lasbes, 40 
pupil of, 105 

Face, 29 

Falciform process, 494 
Fallopian tubes, 484 
Falx, cerebelli, 88 

cerebri, 55 
Fascia, of abdomen, superficial, 340, 350 

anal, 460 

cervical, deep, 170 
superficial, 161 

conjoined, of pelvic and deep pe- 
rineal, 471 

cremasteric, 430 

cribriform, 493 

iliac, 415 

infra-spinous, 241 

infundibuliform, 355 

inter-columnar, 350, 430 

lata, 493, 541 

intermuscular septa of, 502 

of leg, deep anterior, 571 

posterior, 556, 559, 566 

levator, 460 

lumborum, 234 

masseteric, 32 

obturator, 460 

palmar, 274 

parotid, 31 

pectoral, deep, 209 

pelvic, 460, 472 

perineal, deep, 462, 465, 467, 470 
superficial, 456, 402 

perineo-pelvic, 474 

plantar, 584 

propria, 495 

recto-vesical, 460, 473 

of Scarpa, 341 

spermatic, 350, 430 

supra-spinous, 239 

transversalis, 354, 430 

of Tyrrell, 473 
Fauces, 140 
Femoral hernia, 497 

ring, 497 
Fenestra, ovalis, 124 

rotunda, 124 
Fibro-cartilage, radio-ulnar, 283 
Fibrous zones of heart, 311 
Fimbriiu, Fallopian, 484 
Fissure of Glaserius, 124 

great transverse of brain, 80 

of the helix, 121 

sphenoidal, 98 



Fissure — 

of Sylvius, 79 

of the tragus, 121 
Fissures of liver, 399 

of Santorini, 122 
Foramen incisivum, 139 

iacerum anterius, 98 

of Monroe, 63 

optic, 98 

ovale of heart, 302 

sacro-sciatic, great, 538 
small, 538 

of Sommering, 108 

subpubic, 539 

of Winslow, 364 
Foramina Thebesii, 304 
Fovea elliptica, 128 

hemispherica, 128 
Fornix, 61 

anterior crura of, 64 

posterior crura of, 64 
Fossa, amygdaloid, 147 

innominata, 121 

navicularis urethrse, 426 
vaginfe, 476 

ovalis, 302 

scaphoides, 120 
Fossaa, ischio-rectal, 459 

nasal, 136 
Fourchette, 476 
Frasna epiglottidis, 150 

of ileo-cascal valve, 397 
Frsenulum labiorum, 476 
Frsenum linguae, 145 

preputii, 427, 429 

Gall-bladder, 368, 402 
Ganglia, cervical, inferior, 189 
middle, 389 
superior, 188 

semi-lunar, 376 
Ganglion of Andersch, 186 

cardiac, 334 

of cerebellum, 73 

of Cloquet, 140 

Gasserian, 82 

inipar, 454 

lenticular, 94 

of Meckel, 119 

otic, 119 

branches of, 120 

petrous, 180 

spheno-palatine, 119 

on spinal nerves, 290 

submaxillary, 177 
Genu of corpus callosum, 57 
Gimbornat's ligament, 342 
Gland, anti-prostatic, 467 

epiglottic, 197 

lachrymal, 45 



622 



INDEX, 



Gland— 

of Litre, 467 

parotid, 32, 34 

pineal, 65 

pituitary, 79 

prostate, 424, 437 

thymus, 316 

thyroid, 167 
Glands, Brunner's, 394 

Bartholine's, 481 

ceruminous, 122 

Cowper's, 426, 428, 466 

inguinal, 492 

labial, 144 

lymphatic, 492 

mammary, 208 

Meibomian, 42 

molar, 144 

of Lieberkiihn, 394 

Pacchionian, 54, 55 

Payer's, 394 

solitary, 394 

sublingual, 181 

submaxillary, 176 

tracheal, 324 

yulvo -vaginal, 481 
Glandula socia parotidis, 32 
Glandulae agminatse, 394 

odoriferaa, 429 

Pacchioni, 64, 55 

Tysoni, 429 
Glans clitoridis, 477 

penis, 427 
Glisson's capsule, 400 
Globus, major epididymis, 431 

minor epididymis, 431 
Glottis, 201 
Goose's foot of leg, 542 
Graafian vesicles, 488 
Gums, 144 

Hamstring, inner, 543 

outer, 543 
Heart, 299 
Helicotrema, 130 
Helix, 120 

Hernia, congenital, 357 
crural, 489 
diaphragmatic, 417 
encysted, 357 
femoral, 489 

concealed, 499 
inguinal, 349 
direct, 356 
indirect, 356 
oblique, 356 
scrotal, 357 
ventro-inguinal, 356 
Hey's ligament, 494 
Hiatus aorticus, 419 



Hippocampus major, 61 

minor, 61 
Hyaloid body, 108 

membrane, 108 

processes, 109 
Hymen, 477 
Hypothenar eminence, 278 

Eeum, 371, 392 
Incisura tragica, 120 
Incus, 126 

Infundibula of kidney, 407 
Infundibulum of brain, 79 

of ear, 130 

of heart, 305 

of nose, 138 
Integument of breast, 208 
Intercolumnar fibres, 350 
Intestine, lai-ge, 395 

small, 392 
Iris, 105 

Island ofKeil, 60, 79 
Isthmus, uteri, 487 

of Vieussens, 302 

Jejunum, 371, 392 
Joint, ankle, 608 

elbow, 281 

hip, 520 

knee, 595 

shoulder, 243 

temporo-maxillary, 115 

wrist, 283 

Kidneys, 374, 406 

Labia majora, 475 

minora, 476 
Labyrinth, osseous, 127 

membranous, 130 
Lachrymal canals, 45 

ducts, 45 

gland, 45 

papillaa, 45 

sac, 46 
Lactiferous tubes, 209 
Lacuna magna, 427 
Lacus lachrymalis, 44 
Lamina cinerea, 79 

cornea, 61 

cribrosa, 100 

spiralis osseous, 130 
membranacea, 130 
Larynx, 192 
Lens, crystalline, 109 

LiGAMEXTS, 

of auricle of ear, 121 
acromio-clavicular, superior, 243 

inferior, 243 
alar, 600 



INDEX. 



623 



Ligament s — continued. 

annular, of ankle, anterior, 571 
external, 572 
internal, 556 

of radius, 282 

of wrist, anterior, 279 
posterior, 273 
arcuatum externum, 420 

internum, 420 
astragalo-scaphoid, 612 
atlanto-axoid, anterior, 533 
capsular, 533 
posterior, 533 
auricular, 121 

extrinsic, 121 

intrinsic, 121 
of bladder, 366, 472 
calcaneo-cuboid, 613 

-scaphoid, 613 
capsular, of the hip, 521 

jaw, 116 

pisiform bone, 284 

shoulder, 244 

thumb, 285 

vertebrse, 529 
of the carpus, dorsal, 284 

lateral, 284 

palmar, 284 
ciliary, 103 
conoid, 244 
coracoid, 241, 244 
coraco-acromial, 244 
-clavicular, 244 
-humeral, 244 
coronary of liver, 363 

of the knee, 605 
costo-clavicular, 335 
costo-sternal, 335 
costo-transverse, external, 337 
interna], 337 
middle, 337 
costo-vertebral anterior, 336 
cotyloid of hip, 522 
crico-thyroid, lateral, 197 

middle, 197 
crucial of knee, 602 
cruciform, 534 
denticulatum, 287 
deltoid of ankle, 608 
of the elbow, anterior, 281 

lateral, 281 

posterior, 282 
Gimbernat's, 342, 539 
glenoid of scapula, 245 
Iley's, 494 
hip-joint, of the, 520 
ilio-femoral, 522 
ilio-vertobral, 535 
inter-articular of hip, 523 
inter-clavicular, 335 



Ligaments — conthmed. 

interosseous, astragalo-calca- 

neoid, 611 
interosseous tibio-fibular, 606 

tibio-fibular, inferior, 607 
interosseous, radio-ulnar, 283 

of ribs, 336 
inter-spinous, 530 
inter-transverse, 530 
intervertebral, 526 
lateral of the ankle, 608 

jaw, 115 

knee, 599 
of liver, 363 
metacarpal dorsal, "285 

palmar, 285 
moderator, 532 
mucosum, 600 
oblique, radio-ulnar, 283 

of the semilunar cartilages 
605 
obturator, 539 

occipito-atlantal anterior, 530 
capsular, 530 
lateral, 531 
posterior, 530 
occipito-axoid, 532 
odontoid, 532 
orbicular, of elbow, 282 

of hip, 521 
ovarian, 484 
patella, 598 
of phalanges of foot, 616 

of fingers, 285 
posticum of knee, 599 
pterygo-maxillary, 117 
Poupart's, 342, 639 
pubic anterior, 539 

posterior, 539 

superior, 539 
recto-uterine, 366 
rhomboid, 335 
sacro-coccygeal anterior, 535 

posterior, 535 
sacro-iliac, anterior, 536 
oblique, 537 
posterior, 535 
sacro-vertebral, 635 
sacro-sciatic anterior, 537 

posterior, 537 
sacciform, 283 
stellate, 336 
stern o-clavicular anterior, 335 

posterior, 335 
stylo-maxillary, 117 
siib-flava, 529* ' 
sub-pubic, 539 
supra-soapular, 241 
supra-spinous, 629 
suspensory, of clitoris, 477 



624 



INDEX. 



Ligaments — continued. 

suspensory, of liver, 363 

of penis, 341, 349, 429 
tarsal, 610 

tarso-metatarsal, 615 
teres of hip, 523 
of liver, 363 
of uterus, 483 
of thorax, 334 
thyro-arytenoid, 198 
thyro-hyoid, lateral, 197 

middle, 197 
tibio-fibular, anterior superior, 605 
posterior superior, 605 
anterior inferior, 607 
posterior inferior, 607 
transverse, 607 
transverse, of the acetabulum, 522 
of the atlas, 534 
of the metatarsus, 615 
of the scapula, 243 
of the semilunar cartilages, 
605 
trapezoid, 244 
triangular, of scapula, 244 
of abdomen, 352 
of perineum, 467 
of uterus, broad, 366 
vertebral, anterior common, 525 

posterior, common, 525 
wrist, lateral, 283 
anterior, 283 
posterior, 283 
vesico-uterine, 366 
Ligamentum patella), 598 
latum pulmonis, 295 
nuchse, 244, 530 
Limbus luteus, 108 
Linea alba, 344 
Linea3 transversa^ of abdomen, 344, 348 

of corpus callosum, 57, 69 
Lineas semi-lunares, 344 
Lips, 144 
Liquor Cotunnii, 130 

Morgagni, 110 
Liver, 366, 398 
Lobuli testis, 432 
Lobes of the cerebrum, 80 
of cerebellum, 70 
olfactory, 81 
Lobus caudatus, 399 

pneumogastricus, 71 
quadratus, 399 
Spigelii, 399 
Locus, niger, 77 

perforatus lateralis, 79 

medius, 78 
planus, of heart, 306 
Lungs, 325 
Lung, root of, 326 



Lymphatic vessels, arm, 249, 492 
Lyra, 63 

Macula eribrosa, 128 
Malleus, 126 

Massa carnei Jacobi Sylvii, 591 
Mastoid cells, 124 
Meatus auditorius externus, 122 
internus, 131 

urinarius, female, 477 
male, 427 
Meatuses of the nose, 137, 138 
Meckel's ganglion, 119 
Mediastinal space, 296 
Mediastinum, anterior, 297 

middle, 297 

posterior, 297, 315 

superior, 297, 315 

testis, 432 
Medulla oblongata, 73 

spinalis, 289 
Meibomian glands, 42 
Membrana Jacobi, 106, 107 

pigment!, 106 

pupillaris, 106 

Ruyschiana, 106 

tympani, 123 
Membrane, choroid, 106 

crico-thyroid, 198 

hyaloid, 108 

sacciform, 283 
Membranes of the brain, 52 
Membranous part of the urethra, 425, 

437 
Mesentery, 364 
Meso-caecum, 365 
Meso-colon, ascending, 365 

descending, 365 

ti'ansverse, 363 
Meso-rectum, 366 
Mitral valves, 308 
Modiolus, 130 
Mons Veneris, 475 
Morsus diaboli, 484 
Mouth, 143 
Mucous membrane of trachea, 324 

of stomach, 390 

of small intestines, 393 

of large intestines, 396 
Muscles, 

abductor minimi digiti manus, 278 

abductor minimi digiti pedis, 593 

abductor pollicis manus, 277 
pollicis pedis, 587 
internus secundi digiti pedis, 594 
externus secundi digiti pedis, 

595 
tertii digiti pedis, 595 
quarti digiti pedis, 695 

accelerator urinse, 464 



INDEX, 



625 



Muscle s — coiitimied. 

accessorius ad saero-lumbalem, 233 

adductor, brevis, 509 
longus, 508 
magnus, 510, 545 
pollicis manus, 278 
poUicis pedis, 592 
tertii digiti pedis, 593 
quarti digiti pedis, 593 
minimi digiti pedis, 594 
minimi digiti manus, 278 

anconeus, 268 

anti-tragicus, 121 

arytenoideus, 200 

aryteno-epiglottici, 200 

attollens aurem, 48 

attrahens aurem, 48 

of auricles of heart, 312 

azygos uvulae, 150 

of Bell, 424 

biceps flexor cruris, 541 
cubiti, 250 

brachialis anticus, 254 
externus, 256 
internus, 254 

buccinator, 37 

caninus, 39 

cervicalis ascendens, 231 
descendens, 231 

coccygeus, 459 

complexus, 230 

compressor nasi, 39 

compressores urethrae, 468 

constrictor, of pharynx, inferior, 203 
middle, 203 
superior, 203 

coraco-brachialis, 252 

corrugator supercilii, 42 

cremaster, 346 

crico-arytenoideus, lateralis, 201 
posticus, 200 

crieo-thyroideus, 199 

crureus, 507 

deltoid, 238 

depressor anguli oris, 37 
labii inferioris, 37 

superioris alseque nasi, 39 

diaphragm, 417 

digastricus, 165 

erector clitoridis, 477 
penis, 464 
spina3, 233 

extensor carpi radialis brevior, 268 
carpi radialis longior, 268 
carpi ulnaris, 270 
digiti minimi manus, 270 
digitorum brevis pedis, 575 
digitorum communis manus, 269 
digitoi'um longus pedis, 573 
indicis, 272 

58 



Muscle s — continued. 

extensor ossis metacarpi pollicis 
manus, 272 
primi internodii pollicis manus, 

272 
pollicis proprius pedis, 575 
secundi internodii pollicis ma- 
nus, 272 
flexor accessorius pedis, 591 

brevis digiti minimi manus, 

278 
brevis digiti minimi pedis, 593 
carpi radialis, 260 

ulnaris, 261 
digitorum, brevis pedis, 586 
profundus manus, 266, 276 
sublimis manus, 261, 276 
longus, digitorum pedis, 564 

pollicis pedis, 565 
ossis metacarpi pollicis manus, 

277 
pollicis brevis, 278 

pedis, 591 
longus manus, 266 
gastrocnemius, 557 
gemellus inferior, 518 

superior, 518 
genio-hyo-glossus, 154 

-hyoideus, 179 
gluteus maximus, 511 
medius, 513 
minimus, 514 
gracilis, 503 
of Guthrie, 468 
of the heart, 305 
helicis major, 121 

minor, 121 
of Horner, 42 
hyo-glossus, 154, 180 
iliacus internus, 417 
infra-spinatus, 241 
inter-costal external, 292 

internal, 292 
interossei manus, 279 
pedis dorsales, 595 
pedis plantares, 594 
inter-spinales, 236 
inter-transversales, 236 
latissimus dorsi, 222, 225 
laxator tympani, 127 
levator anguli oris, 39 
anguli scapula), 229 
ani, 407 

glandulio thyroidefie, 167 
labii inferioris, 37 
superioris, 38 
superioris, alteque nasi, 39 
menti, 37 
palati, 150 
palpebra>, 92 



626 



INDEX. 



Muscles — continued. 

levatores costarum, 235 

longiores costarum, 236 

urethrae, 468 
longissimus dorsi, 233 
longus colli, 190 
lumbrieales manus, 276 

pedis, 591 
masseter, 111 
multifidus spinge, 235 
mylo-hyoideus, 179 
obliquus abdominis externus, 342 

abdominis internus, 345 

capitis inferior, 237 
superior, 237 

oculi inferior, 97 
superior, 92 
obturator externus, 519 

internus, 518 
occipito-frontalis, 48 
omo-byoideus, 163 
opponens pollicis, 277 
orbicularis oris, 36 

palpebrarum, 41 
palato-glossus, 151 
palato-pharyngeus, 204 
palmaris brevis, 273 

longus, 260 
pectineus, 508 
pectoralis major, 210 

minor, 213 
peroneus brevis, 582 

longus, 581 

tertius, 574 
plantaris, 557 

platysma myoides, 31, 36, 157 
popliteus, 563 
pronator quadratus, 267 

radii teres, 259 
psoas magnus, 416 

parvus, 416 
pterygoideus externus, 112 

internus, 113 
pyramidalis abdominis, 349 

nasi, 39 
pyriformis, 618 
quadratus femoris, 519 

lumborum, 234 

menti, 37 
quadriceps extensor cruris, 506 
rectus abdominis, 348 

anticus major, 189 

antieus minor, 189 

capitis lateralis, 190 

capitis posticus major, 236 
minor, 236 

femoris, 507 

oculi, external, 96 
inferior, 96 
internal, 96 



I Muscles — continued. 
I rectus oculi, superior, 93 

retrahens aurem, 49 
rhomboideus major, 228 

minor, 228 
risorius novus, 38 
sacro-lumbalis, 233 
sartorius, 502 
scalenus anticus, 175 

medius. 175 

posticus, 175 
semi-spinalis colli, 235 

dorsi, 235 
semi-membranosus, 542 

-tendinosus, 542 
serratus, magnus, 220 

posticus inferior, 228 
superior, 228 
of small intestine, 392 

large, 396 
soleus, 558 
sphincter ani externus, 458 

internus, 421 
sphincter vaginge, 481 

vesicae, 424 
spinalis dorsi, 234 
splenius capitis, 229 

colli, 229 
stapedius, 127 

sterno-cleido-mastoideus, 162 
sterno-hyoideus, 163 

-thyroideus, 163 
of stomach, 388 
stylo-glossus, 154, 179 

-hyoideus, 165 

-pharyngeus, 181, 204 
subclavius, 214 
subcrureus, 508 
subscapularis, 221 
supinator radii brevis, 271 

longus, 268 
supra-spinous, 236 
supra-spinatus, 239 
temporal, 49 
tensor, palati, 151 

tarsi, 42 

tympani, 127 

vaginas femoris, 501 
teres major, 221, 242 

minor, 242 
thyro-arytenoideus, 201 

-epiglottici, 200 

"hyoideus, 163 
tibialis anticus, 572 

posticus, 566 
tongue, intrinsic, of, 153 
tracheal, 324 
trachelo-mastoideus, 230 
tragicus, 121 
transversalis abdominis, 346 



INDEX. 



627 



Muscle s — continued. 

transversalis, colli, 230 

pedis, 593 
transversus, auriculee, 121 

perinei, 464 
alter, 464 
trapezius, 224 
triangularis nasi, 39 

oris, 37 

sterni, 293 
triceps extensor cub iti, 222, 242, 255 
of ureters, 424 
vastus externus, 501, 507 

internus, 507 
of ventricles of heart, 312 
of Wilson, 468 
zygomaticus, major, 38 

minor, 38 
Musculi papillares, 304 
pectinati, 304, 307 

Nabotli's ovula, 487 
Nasal duct, 46, 137 

fossae, 136 
Neck, regions of, 165, 166 

superficial parts of, 155 

deep parts of, 184 

Nerves, 

abducentes, 82 

acromial, 161 

articular of knee, 547, 548 

auditory, 83, 131 

auricularis magnus, 32, 160 

auricular, of pneumogastric, 187 

posterior, 35 
buccal, 36, 113 

branches, 33 
cardiac, inferior, 334 

middle, 189, 333 

superior, 189, 333 
cerebral, classification of, 84, 85 

origin of, 80 
chorda tympani, 113, 133 
ciliary, 94, 104 
circumflex, 222, 239, 217 
coccj^geal, 449 
communicans, peronei, 548, 554 

tibialis, 547, 554 
crural, anterior, 415, 504 
cutaneous, external brachial, 216, 
246, 258 

of abdomen, 341 

internal, of arm, 216, 246, 258 

lesser internal, of Wrisberg, 
219, 246 

peroneal, 556 

posterior femoral, 641, 556 
dental anterior, 118 

inferior, 36, 113 



Neeves — continued. 

dental, posterior inferior, 118 

superior, 115, 117 
descendens noni, 182 
digital of foot, 569, 580 
dorsal, posterior, 232 
eighth pair, 83 
facial, 34, 35, 83. 132 

cervical branch of, 161 
fifth pair, 82 
first pair, 80 
fourth pair, 82, 92 
frontal, 50, 91 
genito-crural, 414, 492 
glosso-pharyngeal, 83, 181, 186 
gluteal inferior, 515 

superior, 448, 515 
gustatory, 177 

hemorrhoidal, inferior, 451, 517 
hypoglossal, 83, 177, 186 
infra-orbital, 36, 38, 117 
infra-trochlear, 94 
ilio-scrotal, 360 
intercostal, 294, 348, 358 
intercosto-humeral, 220, 246 
interosseous, anterior, of arm, 267 

posterior of arm, 271 
of Jacobson, 131, 133 
lachrymal, 92 
laryngeal, inferior, 168, 202, 318 

superior, 182, 188, 202 
lingual, 113 
lumbar, 413 

posterior, 232 
lumbo-sacral, 415, 448 
malar, 33, 97 
masseteric. 111, 112 
maxillary branches, 33 
median, 216, 265, 275 
musculo-cutaneous of abdomen, in- 
ferior, 414, 492 
middle, 360, 492 
superior, 360, 492 

arm, 246 

leg, 548, 569, 580 
musculo-spiral, arm, 217, 246, 254 
mylo-hyoid, 113, 177 
nasal, 36, 93 

external, 94 

internal, 36, 93, 141 
naso-palatine, 140 
ninth pair, 83 
obturator, 415, 447, 509 

accessory. 415, 447, 509 
occipitalis major. 51, 232 

minor. 51, 160 
oeulo-motor, 81 
olfactorv, 80, 140 
optic, 81, 96 
palatine, 119 



628 



INDEX, 



Nerve s — continued. 

palatine, anterior, 119, 141 
palmar, median, 275 

ulnar, deep, 275, 279 
superficial, 275 
par vagum, 83, 168, 187 
pathetic, 82, 92 
penis, dorsal of, 453 
perineal, 452 

cutaneous, 453 
superficial, 452, 457 
peroneal, 548 
petrosal, superficial, 120 
pharyngeal, 187 
phrenic, 174, 297, 316 
plantar, external, 590 

internal, 590 
pneumogastrie, 83, 168, 187, 317 
popliteal, external, 544, 548 

internal, 544, 546 
portio dura, 34, 35, 83, 132 

mollis, 83, 131 
pudendal, inferior, long, 453 

superior, long, 452 
pudic, internal, 452, 517 
radial, 263 

respiratory, external, of Bell, 219 
sacral, anterior, 448 

posterior, 232 
saphenous, external, 547, 554 
internal, 500, 552, 555 
peroneal, 548 
sciatic, great, 453, 516, 544 

small, 453, 517 
second pair, 81 
seventh pair, 83 
sixth pair, 82 
spheno-palatine, 119, 140 
spinal accessory, 83, 182, 187, 227 
splanchnic, great, 333 

lesser, 333 
suboccipital, 232 
subscapular, 219 
superficialis colli, 161 
supra-clavicular, 161 
supra-orbital, 50 

supra-scapular, 175, 227, 240, 242 
sympathetic, 188, 413, 454 
temporales profunda, 112 
temporo-auricular, 114 
third pair, 81 
thoracic, inferior, 214 
long, 219 
superior, 211, 212 
tibial, anterior, 548, 579 

posterior, 546, 563 
trifacial, 82 
trigeminal, 82 
tympanic, 131 
ulnar, 217, 254, 265, 275 



Nerve s — continnecl. 
uterine, 455 
Vidian, 119, 131, 132 
Plextis of, 

axillary, 216 

cardiac, 333, 334 

carotid, 185 

cervical, posterior, 232 

coronary of heart, 314 
of stomach, 378 

cystic, 379 

gastric, 376 

gastro-duodenal, 379 

gastro-epiploic, left, 378 
right, 379 

guise, 318 

hemorrhoidal, 454 

hepatic, 373, 376, 379 

hypogastric, 454 

lumbar, 413 

mesenteric, inferior, 383 
superior, 376, 383 

orbital, 99 

ovarian, 455 

pancreatico-duodenal, 37J 

phrenic, 376 

prostatic, 454 

pulmonary, anterior, 318 
posterior, 318 

pyloric, 379 

renal, 376, 385 

sacral, 449. 

solar, 375 

spermatic, 385 

splenic, 376, 378 

tympanic, 134 

vaginal, 455 

vesical, 454 
Nervi molles, 189 
Nodulus cerebelli, 68 
Nose, 134 
Nymphas, 476 
Nares, anterior, 134 
posterior, 149 

(Esophagus, 315, 328 
Omentum gastro-colic, 364 

gastro-hepatic, 363 

gastro splenic, 365 

lesser, 363 

majus, 364 
Optic commissure, 81 

thalami, 60 

tract, 81 
Orbiculare, os, 126 
Origin of cerebral nerves, 80 
Os uteri, externum, 485 
internum, 487 
Os tincae, 485 
Ossicula auditus, 125 



INDEX. 



629 



Otolithes, 131 

Ovaries, 488 

Ovula of Naboth, 487 

Pacchionian glands, 54, 55 
Palate, half arches of, 147 

. soft, 147, 149 
Pancreas, 373, 404 
Papillae, 145 

calyciformes, 146 

conicse, 146 

fungiformes, 146 

of kidney, 407 

lachrymal, 45 
Parotid gland, 32, 3i 
Peduncles, of corpus callosum, 79 

of pineal gland, 64 
Pelvis of kidney, 407 
Penis, 427 
Pericardium, 298 
Pericranium, 49 
Perilymph, 130 
Perineal centre, 458 

joockets, 461 
Perineum, female, 482 

male, 455 
Peritoneum, 362 
Pes hippocampi, 61 
Pharynx, 148, 203 
Pia mater, of brain, 53 

of cord, 287 
Pillars, of fornix, 64 

of external abdominal ring, 350 
Pineal gland, 65 
Pituitary gland, 79 
Pleura costalis, 296 

diaphragmatica, 296 

mediastinalis, 295 

pulmonalis, 295 
Plica semilunaris, 44 
Pons, Tarini, 78 

Varolii, 77 

hepatis, 400 
Popliteal space, 545 
Portio dura, 83, 132 

mollis, 83, 131 
Porus opticus, 100 
Poupart's ligament, 342 
Prepuce of penis, 429 
Preputium clitoridis, 477 
Processus caudatus, 121 

cerebelli ad testes, 68 

cochleariformis, 124 

gracilis, 126 

vermiformis inferior, 72 
superior, 71 
Promontory, 124 
Prostate gland, 424, 437 
Prostatic part of the urethra, 425 
Pulmonary artery, 300, 306, 321, 328 



Pulmonary veins, 302, 307, 321, 328 
Puncta lachrymalia, 45 
Pupil, 105 
Pylorus, 391 
Pyramid, of ear, 124 

of thyroid gland, 167 

of Ferrein, 408 

Raphe of corpus callosum, 57 
Receptaculum chyli, 329, 415 
Rectum, 373, 420, 435 
Rete testis, 433 
Retina, 107 
Rima vaginae, 475 
glottidis, 202 
Ring, abdominal, external, 344 
Rostrum of corpus callosum, 57 

Sac, lesser peritoneal, 364 
Sacculus of ear, 130 

laryngis, 202 
Saphenous opening, 493, 494 

crescentic margin of, 494 
semi-lunar margin of, 494 

vein, internal, 491, 553 

external, 540, 546, 554 
Scala, vestibular, 129 

tympanic, 129 
Sclerotic coat, 100 
Scrotum, 430 ' 
Semicircular canals, 128 

membranous, 130 
Semilunar valves, 306, 309 
Septum, auricularum, 307 

cochleariforme, 125 

crurale, 495 

lucidum of brain, 59 

pectiniforme, 428 
Sheath, infundibuliform, 497 
Shoulder, 238 
Sigmoid, flexure of colon, 372 

valves, 306, 309 
Sinus, auricular, 307 

cavernous, 89, 99 

circular, 89 

lateral, 88 

longitudinal inferior, 55 
superior, 54 

occipital, 88 

palpebral, 44 

petrosal inferior, 89 
superior, 89 

pocularis, 425 

portal, 401 

prostatic, 425 

straight, 88 

transverse, 89 

venosus of heart, 302 
I Sinuses, of Valsalva, 306, 309 
I of uterus, 447 



630 



INDEX. 



Soft palate, 147, 149 
Spheno-maxillary region, 110 
Sphincter vesicEe, 424 
Spinal canal, 286 

cord, 289 
Spleen, 366, 405 
Spongy part of the urethra, 426 
Stapes, 126 
Steno's duct, 32 
Stomach, 366, 368, 387 
Subarachnoid, spaces, 75 

space of cord, 287 
Sublingual gland, 181 
Submaxillary gland, 176 
Substantia gelatinosa, 290 

spongiosa, 290 
Supra-renal capsules, 374, 409 
Suspensory ligament, of the liver, 363 

of the penis, 341, 349, 429 
Sympathetic nerve, 188, 331 
Symphysis pubis, 538 
Synovial, fringes of knee, 601 

membrane of hip, 524 
of jaw, 116 
of knee, 600 
Tapetum, 106 
Taenia semicircularis, 60 

hippocampi, 62 
Tarsal cartilages, 43 
Tendo Achillis, 559 

palpebrarum, 41 
Tentorium cerebelli, 87 
Testicles, 430 
Thalamus nervi optici, 60 
Thoracic duct, 191, 315, 329 
Thorax, 291 
Thyroid cartilage, 194 

gland, 167 
Tongue, 152 

nerves of, 154 
Topography of mouth, fauces, and pha- 
rynx, 143 
Tonsils, 148 

of cerebellum, 68 
Torcular Herophili, 54 
Trachea, 321 
Tragus, 120 
Tricuspid valves, 305 
Trigone vesicale, 423 
Tripod of Haller, 376 
Tuber cinereum, 79 
Tubercula quadrigemina, 66 
Tubercalum Loweri, 302 
Tubes of Ferrein, 408 
Tubuli recti, 433 

seminiferi, 432 

uriniferi, 408 
Tunica, albuginea testis, 431 
serosa, 101, 104 
vaginalis testis, 431 



Tunica vasculosa testis, 432 
Tympanum, 123 
Tyson's glands, 429 

Ureters, 374, 409 
Urethra, female, 482 

male, 425 
Uterus, 483 
Utriculus, 130 
Uvea, 105 
Uvula cerebelli, 68 

palati, 149 

vesicae, 424 

Vagina, 478 • 

columns of, 479 
Valve of Bauhin, 397 

of brain, 68 

Eustachian, 303 

ileo-ca?cal, 397 

ileo-colic, 397 

mitral, 308 

of Thebesius, 304 

tricuspid, 305 
Valves, semilunar, 306 

sigmoid, 306, 309 
Valvule conniventes, 393 
Vasa recta, 433 

brevia, 376 

eflferentia, 433 

vorticosa, 100, 104 
Vas aberrans, 434 

deferens, 433 
Veins, 

axillary, 218 

azygos, major, 315, 330 
minor, 330 
superior, 330 

basilic, 246 

median, 246 

bronchial, 317, 322 

cava ascendens, 412 

descendens, 300, 317 

cephalic, 211, 212, 245 

communicans, of arm, 246, 248 

coronary, of heart, 304, 314 
of stomach, 378 

of corpora cavernosa, 429 

dorsalis penis, 429 

dorsal of foot, 570 

dorsal arch of foot, 570 

emissaries of Santorini, 52 

facial, 158 
I femoral, 505 

of forearm, superficial, 257 
I Galeni, 64 

of head, superficial, 52 

hepatic, 400, 402 

innominata, 168, 316 

internal maxillarv, 115 



INDEX. 



631 



YiEi'ss—co7itt7med. 

intercostal superior, 317 
iliac, common, 413 

internal, 445 
ilio-lumbar, 445 
jugular, anterior, 158 

external, 158 

internal, 168, 185, 192 
of leg, deep-seated, 562, 579 
median, 246 

cephalic, 245 
mammary, internal, 317 
mesenteric, superior, 382 

inferior, 383 
ophthalmic, 96 
ovarian, 446 
popliteal, 546, 549 
portal, 401 

profunda femoris, 506 
pulmonary, 302, 307, 321, 328 
pericardiac, 317 
phrenic, superior, 317 
renal, 385 
sacral, lateral, 445 

middle, 445 
saphenous, internal, 491, 553 

ext-^rnal, 540, 546, 554 
spermatic, 385, 435, 446 
of the spinal cord, 288 
splenic, 376 
subclavian, 174 
supra-renal, 386 
transversa, 317 
thyroid, inferior, 317 
thymic, 317 
umbilical, 400 
uterine, 447 



Veins — co7itimied. 
Plexus of, 

choroides, 61 

hemorrhoidal, 421, 446 

pampiniformis, 435 

tracheal, 166 

vaginal, 447 

vesico-prostatic, 446 
Velum, interpositum, 63 

medullare, posterior, 68 
Venae comites, brachial, 254 
Vena portae, 401 
Ventricle of Arantius, 68 
Ventricles of the brain, 

fifth, 59 

fourth, 67 

lateral, 59 

third, 64 
of the heart, right, 300, 301, 304 

left, 300, 301, 308 
of the larynx, 201 
Vermiform processes, 71, 72 
Verumontanum, 425 
Vesical triangle, 423 
Vesiculae seminales, 434 
Vestibule, 128 
Vestibulum vaginae, 477 
Villi, 393 

Viscera, abdominal, relations of, 366 
Vesicles, Graafian, 488 
Vitreous humor, 108 
Vulva, 475 

Wharton's duct, 177, 179 

Zonula of Zinn, 109 
Zones of heart, fibrous, 311 



THE END. 



